Using non-keyboard input devices: interviews with users in the workplace

A study of 45 non-keyboard input device (NKID) users was undertaken at nine organisations to investigate the extent, pattern and method of NKID usage, workstation configurations, postures adopted and musculoskeletal symptoms. A number of methods were used: work activity diaries, interviews, observations and postural assessments. A range of NKID were seen including the mouse, touchscreen, joystick, trackball, and tablet and pen; however, the mouse was the most commonly used device. Use of an input device varied from 2% to 100% of the working day. Workers undertook common tasks using a variety of methods (e.g. pull down menus, icons, device buttons). Users reported problems associated with the use of some devices, e.g. poor maintenance, lack of device responsiveness. Musculoskeletal pain and discomfort (e.g. stiffness and discomfort in the hands and wrist) was reported by 45% (n=19) of mouse users and 16% (n=5) of other NKID users. Workstation configurations varied and in some cases constrained the position of the input device, resulting in users having to work with the device at some distance away from the body. Despite the existence of regulations and guidance, this paper indicates that there are still many problems related to NKID use at computer workstations.

Relevance to industry

The reliance of many software applications on NKID (e.g. mouse, trackball, touchpad, joystick, touchscreen) necessitates the investigation of their use in the workplace. Whilst the performance aspects of NKID (e.g. speed) have been well researched, the possible implications for user health have received little attention in the UK.     

Hardware Support for Navigating Large Digital Documents

Buxton and Myers (1986 Buxton, W. and Myers, B. 1986. A study in two-handed input. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, : 321–326.  [Google Scholar]) compared a specialized document navigation device and a scrollbar. Their device tracked finger movements along two touch-sensitive areas: one for absolute movement and one for relative movement. They found that their system was faster when navigating a 5-page document. We identified finger-tracking issues with the Buxton and Myers device for larger documents (100 pages) and developed an alternative device employing a range sensor and rotary encoder to track finger movement. We ran a new experiment comparing the traditional scrollbar, the Buxton and Myers design, and our new design. Both the Buxton and Myers design and our new design were poorly received by users compared to the scrollbar. Our results indicate that in a large document, factors beyond finger tracking accuracy influence the performance of a device providing absolute movement. From these results, we identify possible improvements necessary to implement effective and practical absolute navigation devices.     

Mushaca: A 3-Degrees-of-Freedom Mouse Supporting Rotation

Based on kinesiology research demonstrating that translation and rotation are inseparable actions in the physical world, we present Mushaca, a 3-degrees-of-freedom mouse that senses rotation in addition to traditional planar position. We present an optical realization of the Mushaca device based on two optical sensors and then evaluate the device through a series of controlled experiments. Our results show that rotation is indeed a useful input modality for a pointing device, and also give some insight into how users perceive the changing coordinate system of the rotating mouse and adapt to this change through kinesthetic learning.     

Effectiveness of hand- and foot-operated secondary input devices for word-processing tasks before and after training

Previous research has shown that, without practice, users are slower using the foot than the hand to control input devices. This study compared the performance (before and after practice) of users operating a foot-controlled secondary input device (foot mouse) with the performance of users operating a hand-controlled secondary input device (hand trackball) to complete four word-processing tasks requiring various amounts of keyboard and secondary input device use. Before practice, hand trackball performance was better on all tasks. After practice, hand trackball performance was better on all tasks except the task requiring the greatest amount of keyboard use, for which there was no significant difference between devices. For all tasks, practice improved performance with the foot mouse but not with the hand trackball. These findings suggest that, with enough practice, it may be efficient for users to use a foot input device for tasks that also require keyboard input.     

Where Does the Mouse Go? An Investigation into the Placement of a Body-Attached TouchPad Mouse for Wearable Computers

We investigated the effects of placement of a TouchPad input device on a user's body for the control of a wearable computer. This study involved 25 subjects performing selection tasks with a TouchPad mouse while wearing a wearable computer on their back and using a head-mounted display. Each subject performed the tasks in 27 different combinations of four postures (sitting, kneeling, standing and prone) and seven different placements of the TouchPad mouse on the subject's body (forearm, thigh by 2, torso by 2, and upper arm by 2). We measured the time and error rate to complete the selection of a circular target. The results for the effects due to posture showed that there were similar time effects for sitting, standing and kneeling. When examining the effects resulting from mouse position, the front of the thigh was shown to be the best position of the mouse. When the posturing and mouse position conditions were combined, the results indicated that the thigh front mouse position would be most appropriate for sitting, kneeling and standing postures, and the forearm mouse position would be best for the prone position.     

Constrained data-driven optimal iterative learning control

A constrained optimal ILC for a class of nonlinear and non-affine systems, without requiring any explicit model information except for the input and output data, is proposed in this work. In order to address the nonlinearities, an iterative dynamic linearization method without omitting any information of the original plant is introduced in the iteration direction. The derived linearized data model is equivalent to the original nonlinear system and reflects the real-time dynamics of the controlled plant, rather than a static approximate model. By transferring all the constraints on the system output, control input, and the change rate of input signals into a linear matrix inequality, a novel constrained data-driven optimal ILC is developed by minimizing a predesigned objective function. The optimal learning gain is unfixed and updated iteratively according to the input and output measurements, which enhances the flexibility regarding modifications and expansions of the controlled plant. The results are further extended to the point-to-point control tasks where the exact tracking performance is required only at certain points and a constrained data-driven optimal point-to-point ILC is proposed by only utilizing the error measurements at the specified points only.     

To twist,roll, stroke or poke? A study of input devices for menu navigation in the cockpit

Modern interfaces within the aircraft cockpit integrate many flight management system (FMS) functions into a single system. The success of a user's interaction with an interface depends upon the optimisation between the input device, tasks and environment within which the system is used. In this study, four input devices were evaluated using a range of Human Factors methods, in order to assess aspects of usability including task interaction times, error rates, workload, subjective usability and physical discomfort. The performance of the four input devices was compared using a holistic approach and the findings showed that no single input device produced consistently high performance scores across all of the variables evaluated. The touch screen produced the highest number of ‘best’ scores; however, discomfort ratings for this device were high, suggesting that it is not an ideal solution as both physical and cognitive aspects of performance must be accounted for in design.

Practitioner summary: This study evaluated four input devices for control of a screen-based flight management system. A holistic approach was used to evaluate both cognitive and physical performance. Performance varied across the dependent variables and between the devices; however, the touch screen produced the largest number of ‘best’ scores.     

Directional bias in scrolling tasks: a study of users' scrolling behaviour using a mobile text-entry strategy

Mobile devices with limited interaction controls often employ cyclic scrolling for retrieval tasks. In this paper the scrolling behaviour of users entering text using a tree-key input technique based on two-phase cyclic character scrolling is studied. The results show that users have a tendency to scroll more from left-to-right than from right-to-left. However, users do also use the right-to-left functionality to both speed up their text entry task by choosing the shortest path and to make navigational corrections, suggesting that it is appropriate to provide bidirectional scrolling functionality in user interfaces on constrained mobile devices. In situations where a device architect is constrained to providing only unidirectional scrolling, the results suggest that a right-directional design is preferred over a left-directional design.     

支持多模态交互的桌面增强显示系统

传统的显示设备在受限的物理空间内难以向用户呈现大量画面和复杂内容,而AR头戴式显示设备通过将三维的可视化内容悬浮显示在用户眼前,在不占用额外物理空间的条件下可增强真实世界的画面显示,呈现形式更为丰富的内容。设计AR虚拟空间与真实电脑画面虚实融合的桌面增强显示系统。通过基于二维码识别的空间定位技术将真实电脑画面映射至虚拟空间内,实现交互空间的统一,同时构建窗口布局计算模型使得系统可以根据用户自定义参数自动生成窗口并设置其布局。在此基础上,利用蓝牙通信、网络传输、操作系统底层映射和结合视线检测的语音识别等技术支持手势、键鼠和语音的多模态交互方式,设计鼠标移动策略以扩展鼠标在三维空间下的多种操作模式。实验结果表明,与隔空手势交互、鼠标交互等传统交互方式相比,该系统在处理常见电脑任务时平均耗时节省10%~30%,具有较高的交互效率,且在跨窗口连续移动和瞬间跳转时能够正确显示鼠标位置。     

Evidence-based guidelines for the wise use of computers by children: Physical development guidelines

Computer use by children is common and there is concern over the potential impact of this exposure on child physical development. Recently principles for child-specific evidence-based guidelines for wise use of computers have been published and these included one concerning the facilitation of appropriate physical development. This paper reviews the evidence and presents detailed guidelines for this principle. The guidelines include encouraging a mix of sedentary and whole body movement tasks, encouraging reasonable postures during computing tasks through workstation, chair, desk, display and input device selection and adjustment and special issues regarding notebook computer use and carriage, computing skills and responding to discomfort. The evidence limitations highlight opportunities for future research. The guidelines themselves can inform parents and teachers, equipment designers and suppliers and form the basis of content for teaching children the wise use of computers.

Statement of Relevance: Many children use computers and computer-use habits formed in childhood may track into adulthood. Therefore child–computer interaction needs to be carefully managed. These guidelines inform those responsible for children to assist in the wise use of computers.     

Constrained motion control of flexible robot manipulators based on recurrent neural networks

In this paper, a neural network approach is presented for the motion control of constrained flexible manipulators, where both the contact force everted by the flexible manipulator and the position of the end-effector contacting with a surface are controlled. The dynamic equations for vibration of flexible link and constrained force are derived. The developed control, scheme can adaptively estimate the underlying dynamics of the manipulator using recurrent neural networks (RNNs). Based on the error dynamics of a feedback controller, a learning rule for updating the connection weights of the adaptive RNN model is obtained. Local stability properties of the control system are discussed. Simulation results are elaborated on for both position and force trajectory tracking tasks in the presence of varying parameters and unknown dynamics, which show that the designed controller performs remarkably well.     

Design of reconfigurable coupled-serial-chain-based manipulation assistive aids

Our goal is to design a reconfigurable single degree-of-freedom (dof) articulated manipulation assistive aid, whose end-effector is required to closely approximate a series of constrained planar paths. To this end, we investigate the viability of the coupled-serial-chain configuration manipulator design created by constraining the relative rotations of a revolute-jointed serial-chain manipulator with linear cable–pulley couplings. The forward kinematics equations take the form of a finite trigonometric series in terms of the input crank rotations. Our proposed Fourier-based synthesis method exploits this special structure to facilitate the design synthesis of such manipulators. We then examine design enhancements, to permit this manipulator to be reconfigured for multiple sets of constrained end-effector tasks, by controlled variation of the principal structural parameters. Particular attention is paid to the creation of a physical prototype, which facilitates such reconfiguration.     

Adaptive control based on fast online algebraic identification and GPI control for magnetic levitation systems with time-varying input gain

This paper considers the position tracking problem of a voltage-controlled magnetic levitation system (MLS) in the presence of modelling errors caused by uncertainties in the system’s physical parameters. An adaptive control based on fast online algebraic parameter estimation and generalised proportional integral (GPI) output feedback control is considered as a control scheme candidate. The GPI controller guarantees an asymptotically exponentially stable behaviour of the controlled ball position and the possibilities of carrying out rest-to-rest trajectory tracking tasks. The nature of the control input gain in an MLS is that of a state-dependent time-varying gain, reflecting the nonlinear character of the magnetic force with regard to the distance and the properties of the metallic ball. The system gain has therefore been locally approximated using a periodically updated time polynomial function (of second degree), where the coefficients of the polynomial are estimated during a very short period of time. This estimation is achieved using the recently introduced algebraic online parameter estimation approach. The stability of the closed-loop system is demonstrated under the assumption that no external factors cause changes in the parameter during the time interval in which the stability is analysed. Finally, experimental results are presented for the controlled MLS demonstrating the excellent stabilisation and position tracking performance of the control system designed in the presence of significant nonlinearities and uncertainties of the underlying system.     

Convergence and robustness of a discrete-time learning control scheme for constrained manipulators

The constrained motion control is one of the most common control tasks found in many industrial robot applications. The nonlinear and nonclassical nature of the dynamic model of constrained robots make designing a controller for accurate tracking of both motion and force a difficult problem. In this article, a discrete-time learning control problem for precise path tracking of motion and force for constrained robots is formulated and solved. The control system is able to reduce the tracking error iteratively in the presence of external disturbances and errors in initial condition as the robot repeats its action. Computer simulation result is presented to demonstrate the performance of the proposed learning controller. © 1994 John Wiley & Sons, Inc.     

Active Disturbance Rejection Control of a Magnetic Suspension System

This paper proposes a novel output feedback control scheme for robust stabilization and tracking tasks in a magnetic suspension system. Active disturbance rejection control, differential flatness and on‐line asymptotic disturbance estimation are properly used for the proposed control synthesis. The controlled system is subjected to a wide spectrum of unknown significant matched and unmatched disturbances due to external forces and voltages, parametric uncertainties, control and state‐dependent perturbations and possibly input unmodeled dynamics. The effectiveness and robustness of the proposed active disturbance control scheme is verified by computer simulations for the robust tracking of a rest‐to‐rest reference position trajectory specified to firstly stabilize the suspended mass at a desired vertical position and next transfer it to another equilibrium position for both continuous and switched control voltage signals.     

Development of a computer input device for patients with tetraplegia

It is necessary for medical staff members to evaluate the computer input ability of patients with spinal cord injury (SCI) during the patients' rehabilitation. In this paper, we describe a system for measuring and evaluating the computer input ability of SCI patients. We measured the position locus of the mouse cursor when a patient operates a computer using a ball mouse. After this measurement, we calculated three time parameters to evaluate the computer input ability of the patient. In addition, we developed a new computer input device for patients, and showed by means of the three time parameters that this device was effective for some patients.     

Quasi-min-max output-feedback model predictive control for LPV systems with input saturation

In the research field of model predictive control (MPC), an output-feedback-type MPC method is consistently required for controlling a wide range of constrained systems. In this paper, we propose a two-stage control strategy for polytopic linear parameter varying (LPV) systems subject to input constraints. This strategy consists of a modified quasi-min-max output-feedback MPC method and a novel terminal output-feedback robust control technique. The proposed control mechanism involves the system states to be first controlled via the MPC method to be driven into a prescribed neighborhood of the origin, and then, the terminal output-feedback robust control method guaranteeing the input constraints is applied to make such states converge to the origin. It is also verified that our control method guarantees the closed-loop stability and feasibility in the presence of model uncertainties and input constraints. Finally, a numerical example is given to demonstrate its effectiveness.     

Design and evaluation of haptic effects for use in a computer desktop for the physically disabled

The human–computer interface remains a mostly visual environment with little or no haptic interaction. While haptics is finding inroads in specialized areas such as surgery, gaming, and robotics, there has been little work to bring haptics to the computer desktop, which is largely dominated today by the GUI/mouse relationship. The mouse as an input device, however, poses many challenges for users with physical disabilities, and it is believed that a haptically enhanced interface could have significant impact assisting in target selection. This paper presents a study intended to evaluate haptic effects used with a force feedback mouse on a computer desktop and a prediction algorithm designed to focus those effects on the desired target. Results of the experiment were partially successful and indicated future directions for improvement. The paper introduces the proposed framework and presents experimental results from targeting tasks using differing haptic effects with a group of physically disabled users.     

Head-Tracked Stereo Viewing with Two-Handed 3 D Interaction for Animated Character Construction

In this paper, we demonstrate how a new interactive 3 D desktop metaphor based on two-handed 3 D direct manipulation registered with head-tracked stereo viewing can be applied to the task of constructing animated characters. In our configuration, a six degree-of-freedom head-tracker and CrystalEyes shutter glasses are used to produce stereo images that dynamically follow the user head motion. 3 D virtual objects can be made to appear at a fixed location in physical space which the user may view from different angles by moving his head. To construct 3 D animated characters, the user interacts with the simulated environment using both hands simultaneously: the left hand, controlling a Spaceball, is used for 3 D navigation and object movement, while the right hand, holding a 3 D mouse, is used to manipulate through a virtual tool metaphor the objects appearing in front of the screen. In this way, both incremental and absolute interactive input techniques are provided by the system. Hand-eye coordination is made possible by registering virtual space exactly to physical space, allowing a variety of complex 3 D tasks necessary for constructing 3 D animated characters to be performed more easily and more rapidly than is possible using traditional interactive techniques. The system has been tested using both Polhemus Fastrak and Logitech ultrasonic input devices for tracking the head and 3 D mouse.     

Notebook input devices put to the age test: the usability of trackpoint and touchpad for middle-aged adults

In two experiments, the usability of input devices integrated into computer notebooks was under study. The most common input devices, touchpad (experiment 1) and trackpoint (experiment 2) were examined. So far, the evaluation of mobile input devices has been restricted to younger users. However, due to ongoing demographic change, the main target group of mobile devices will be older users. Therefore, the present study focused on ageing effects. A total of 14 middle-aged (40–65 years) and 20 younger (20–32 years) users were compared regarding speed and accuracy of cursor control in a point-click and a point-drag-drop task. Moreover, the effects of training were addressed by examining the performance increase over time. In total, 640 trials per task and input device were executed. The results show that ageing is a central factor to be considered in input device design. Middle-aged users were significantly slower than younger users when executing the different tasks. Over time, a significant training effect was observed for both devices and both age groups, although the benefit of training was greater for the middle-aged group. Generally, the touchpad performance was higher than the trackpoint performance in both age groups, but the age-related performance decrements were less distinct when using the touchpad.