机器人辅助机械加工单元控制系统设计

介绍一种机器人辅助机械加工单元控制系统,阐述整个单元的布局及机器人过程控制、气动控制原理、PLC控制原理及软件编程等模块的设计方法。选取S7-200作为系统控制器,主机单元为CPU226,采用GP4401WW作为触摸屏显示器。通过系统调试实现了机器人对数控机床的自动化上下料,降低了劳动强度,提高了生产效率。     

机器人在压缩机壳体冲孔上的应用

在压缩机壳体冲孔的工艺中引入机器人技术,根据工艺时序图及机器人的模拟动作时间设计了机器人动作节拍;对实际生产时两台机器人的分工协作设计了干涉区,以避免碰撞;通过修改机器人夹爪设计和在伺服马达处加装散热风扇,解决轴马达温度过热问题。通过应用机器人提高了生产效率,改善了劳动条件。为机器人在自动化生产方面进行了一些有益的探索。     

基于ADAMS的四轴冲压搬运机器人的运动学分析及仿真

针对现在冲压行业升级改造的实际需求,设计开发一种灵活性高、控制简单的四轴冲压搬运机器人,利用Solidworks建立机器人实体模型;采用D-H法构建了运动学方程,对该机器人进行了运动学正解与反解;通过ADAMS软件对机器人进行了运动学仿真,规划了搬运轨迹;并通过对末端执行器X、Y、Z方向的位移、速度、加速度仿真曲线的分析与评估,验证设计的合理性,并为实现四轴冲压搬运机器人运动控制奠定了基础。     

Tool-Center-Point control of the KAI manipulator using constrained QP optimization

The KAI manipulator is a four joint mobile manipulator, which will be used within the German road clearance package to investigate improvised explosive devices and ordnance from within an armored vehicle. To improve handling of the manipulator, a Tool-Center-Point (TCP) control is implemented. By using constrained quadratic optimization (cQP) it is possible to allow for the control of the manipulator within three different operating spaces. The QP is formulated to account for constraints in the joint angular rates and TCP velocities, as well as additional velocity constraints, e.g. on the movement of the center of mass of the manipulator. The proposed algorithm is able to handle redundant as well as non redundant manipulator kinematics. By using an efficient QP solver the algorithm can be used within a real-time trajectory generation scheme. The performance of the algorithm is demonstrated using simulation results and validated by measurements of the TCP control.     

Effect of practice on similar and dissimilar skills in patient transfer through training with a robot patient

With the number of hospital stays increasing, nurses require more training to handle a variety of patients. However, time for training in nursing schools is limited, and students lack the opportunity to practice on a diverse variety of patients. Using a robot to simulate actual patients, this study observes the learning transfer effect of practice on practice-similar and practice-dissimilar skills from one patient to another, and investigates which types of practice suit which kinds of training. An experiment was conducted by administering a pre-test, practice, a post-test, and a transfer test to two groups (N?=?8), each with different practice-related skills. The evaluation used a checklist covering required skills that were either similar or dissimilar across groups, depending on their practice. The effect of practice can be observed through a comparison of skills similar to one group but dissimilar to the other. The results show that practice facilitates learning transfer on similar skills but not, or to a lesser degree, on dissimilar skills. Furthermore, if skills needed to handle given symptoms are unfamiliar or inaccessible to students, practice related to those symptoms should be emphasized through simulated training with robots.     

Data‐Driven Kinematic Control for Robotic Spatial Augmented Reality System with Loose Kinematic Specifications

We propose a data‐driven kinematic control method for a robotic spatial augmented reality (RSAR) system. We assume a scenario where a robotic device and a projector‐camera unit (PCU) are assembled in an ad hoc manner with loose kinematic specifications, which hinders the application of a conventional kinematic control method based on the exact link and joint specifications. In the proposed method, the kinematic relation between a PCU and joints is represented as a set of B‐spline surfaces based on sample data rather than analytic or differential equations. The sampling process, which automatically records the values of joint angles and the corresponding external parameters of a PCU, is performed as an off‐line process when an RSAR system is installed. In an on‐line process, an external parameter of a PCU at a certain joint configuration, which is directly readable from motors, can be computed by evaluating the pre‐built B‐spline surfaces. We provide details of the proposed method and validate the model through a comparison with an analytic RSAR model with synthetic noises to simulate assembly errors.     

A KinFu based approach for robot spatial attention and view planning

When a user and a robot share the same physical workspace the robot may need to keep an updated 3D representation of the environment. Indeed, robot systems often need to reconstruct relevant parts of the environment where the user executes manipulation tasks. This paper proposes a spatial attention approach for a robot manipulator with an eye-in-hand Kinect range sensor. Salient regions of the environment, where user manipulation actions are more likely to have occurred, are detected by applying a clustering algorithm based on Gaussian Mixture Models applied to the user hand trajectory. A motion capture sensor is used for hand tracking. The robot attentional behavior is driven by a next-best view algorithm that computes the most promising range sensor viewpoints to observe the detected salient regions, where potential changes in the environment have occurred. The environment representation is built upon the PCL KinFu Large Scale project [1], an open source implementation of KinectFusion. KinFu has been modified to support the execution of the next-best view algorithm directly on the GPU and to properly manage voxel data. Experiments are reported to illustrate the proposed attention based approach and to show the effectiveness of GPU-based next-best view planning compared to the same algorithm executed on the CPU.     

Hand gesture recognition using valley circle feature and Hu’s moments technique for robot movement control

Hand gesture recognition is a simpler and more natural way of human computer interaction. The goal of this paper is to detect the continuous gestures and use them to convey information for the robot movement control. So the hand gesture recognition requires fast and extremely robust. In this paper, three strategies were used to realize the hand gesture recognition: (1) the valley circle (VC) was created for the first stage of 6 fingertip numbers classification; (2) the hybrid feature vector of Hu’s moments, convexity and compactness (HCC) were constructed for the second stage of gesture recognition of the remainder unknown gesture classes; (3) a new template matching recognition (NTMR) algorithm was proposed to realize 10 gesture classes recognition. To test the hand gesture recognition method, the robot movement control system was built. It is experimental proved that the NTMR algorithm is effective and corrective for the hand gesture recognition. It increased the recognition accuracy by 4% and decreased the recognition duration by 112 ms compared with Hu’s moment method. It had good performances of the real-time hand gesture acquisition and information conveyance, and it had the invariant properties when the gesture was rotated and shifted and scaled.     

Exploiting robotic link deflection for low-cost force measurement in manufacturing

A custom, low-cost force measurement system for manufacturing is presented that exploits robotic link deflection for measurement purposes instead of utilizing a commercially purchased load cell. Force measurement can be an important aspect to many manufacturing processes, as it can allow for force feedback control or other process-planning related operations, such as tool-workpiece autozero or through-the-tool joint tracking. This system is demonstrated on a machine that is used for Friction Stir Welding research, and a Finite Element Analysis is also conducted on the robotic link that is used for axial force measurement purposes. This system may be particularly attractive to small businesses or low-volume manufacturers whose smaller operating budgets may normally prohibit them from implementing force measurement systems.