Traditional magnetic wall-climbing robot can not meet well the requirements on manoeuvrability, loading ability and self-adaptability on irregular ferromagnetic surface at the same time. A novel magnetic-wheel unit was introduced to solve this problem. The magnetic-wheel unit consists of wheel, permanent-magnet blocks and connecting parts. Its characteristic is that the permanentmagnet block is set symmetrically around the wheel and there is a distance between the block and the surface. There is a stable adsorption force between the unit and the surface, whatever the surface has different curvature radius. A novel wall-climbing robot, comprising of three units, was designed. Finite element analysis results show that the adsorption force varies less than 6%, when the robot is placed on the cylindrical surface with a curvature radius bigger than 1.5 m. the results are better than traditional mechanism.

Conventional dexterous hands have too many DOFs, their driver systems are too big to be installed in a humanoid robot arm, and their controls are too complex. This paper develops an under-actuated passive adaptive grasp humanoid robot hand named TH-1 Hand with control of grasping force. With the humanoid appearance and size, TH-1 Hand is light, fewer DOFs, and can be easily controlled. Its motors and driver circuit boards are embedded in itself. These features make it fit to be installed in a humanoid robot arm. In addition, for stably grasping operation, a mechanical finger with control of grasping force is designed and applied in TH-1 Hand’s index. To get more DOFs with fewer drivers, a novel under-actuated passive adaptive grasp mechanical finger is designed and applied in TH-1 Hand’s thumb.

Purpose – This paper seeks to present recent work designing a mechanical robotic hand for self-adaptive grasping, human-like appearance, which can be used in a humanoid robot. Conventional robotic devices are relatively complex, large, cumbersome and difficult to be installed in a humanoid robot arm. Under-actuated robot hands use less motors to drive more rotating joints, thus to simplify the mechanical structure, decrease the volume and weight and finally lower the difficulty of control and the cost. Design/methodology/approach – A novel under-actuated finger mechanism is designed, which is based on a gear-rack mechanism, spring constraint and an active sleeve middle phalanx. The principle analyses of its self-adaptive grasp and end power grasping are given. A new multi-fingered hand named as TH-3R Hand is designed based on the finger. Findings –The design finger mechanism can be used in a robotic hand to make the hand obtain more DOF with less actuators, and good grasping function of shape adaptation, decrease the requirement of control system. TH-3R Hand has 5 fingers, 15 DOF. Its all fingers are similar. TH-3R Hand has many advantages: it is simple in structure, light in weight, easy in control and low in cost. TH-3R Hand can passively adapt different shapes and sizes of the grasped object. Experimental studies have demonstrated the self-adaptation in grasping of the finger. Research limitations/implications – The implication of this research is that under-actuated robotic hands are appropriate for the missions of grasping different objects. The limitation of the research to date is that issues of sensors, control, and communication have not yet been addressed. Practical implications – Key technologies of the design under-actuated finger and TH-3R Hand, with self-adaptive grasping, human-like appearance and low cost lightweight, are feasible. These technologies have the potential to make a significant impact on the search and humanoid robotic hands. Originality/value – These results present a self-adaptive under-actuated grasp concept and a humanoid robotic hand with under-actuated gear-rack mechanism.

为了提高图像上直线检测的鲁棒性和精度，提出一种灰度投影积分(GPI)方法。GPI方法将需要检测的图像直接在直角坐标空间沿某个投影方向进行投影，将对应到同一投影点的像素灰度值进行累加，得到灰度投影积分向量，再旋转投影方向计算不同投影方向的灰度投影积分向量，从而得到一个原图像的灰度投影积分矩阵，再由该矩阵的极值元素所在的行和列求出图像中直线的方程。实验结果表明，GPI方法不需要事先提取边缘点，就能够快速准确地检测出图像中的直线，避免了传统方法在提取边缘点时阈值选取不当带来的直线检测误差。

The part coordinates are always calibrated before the arc welding robot carries out some tasks. Traditional methods use expensive and comp licated devices for measuring. A novel method to quickly calibrate the part coordinateswas p resented, using only the internal coder data of robot and coordinates transform calculation to get the coordinates transform matrix between the part frame and the basic frame of robot. It was easy to operate and its calibration result was precise. The method was imbedded in the self-developed off-line programming software for MOTO-MAN SK6 arc welding robot. Based on the algorithm and off-line programming, robot writing was realized. Experimental results showed the validity of the calibration method.

This paper aims at providing a method to realize selfadaptive robotic hand, especially the under-actuation function among several fingers by springs. Considering its advantages of increasing stability of grasping and reducing difficulty of controlling, many studies on underactuated mechanisms have been carried out. Compared with traditional under-actuated mechanisms for single multi-joint finger, this paper proposed a novel multifinger under-actuated mechanism. By setting torsional springs around root joint shaft, the mechanism realizes that one motor drives root joints of multiple fingers. The main design principle is introduced through analysis. This mechanism can be used as root joints of index, middle, ring and little fingers. It also realizes passive adaptive grasp to objects of different shapes and sizes with a proper grasping force. It has high grasping stability and low control requirement.

adopted to monitor fast human-arm motion for analyzing human motion characteristics. An imaging system is set up, and black marks are adopted to label human arm’s position during experiments. An algorithm of image sequence processing is developed for extracting the center points of the marks. Then, the angle, velocity and acceleration of human arm joints during the motion are calculated. The results can provide motion control scheme of humanoid robot arm.

This paper proposed a design idea of a novel under-actuated finger mechanism, and analyzed its principle and designed the finger mechanism. The finger is designed based on a gear-rack mechanism, spring constraint and particular active middle-segment, which is passively adaptive in grasping objects. A new multi-fingered hand named as TH-3R Hand is designed based on the finger. TH-3R Hand has 5 fingers, 15 DOF. Its all fingers are similar. TH-3R Hand has many advantages: it is simple in structure, light in weight, easy in control and low in cost. TH-3R Hand can passively adapt different shapes and sizes of the grasped object. It can be mounted in humanoid robot hand to make the hand obtain more DOF with less actuators, and good grasping function of shape adaptation, decrease the requirement of control system.

Laser welding has a quite high demand on trajectory accuracy of articulated robot. To improve dynamic trajectory accuracy of articulated robots for laser welding, a novel 3D seam tracking method is proposed based on stereo visual feedback control. The method constructs a visual feedback control system with two convergent cameras mounted at the end of industrial robot. A tool coordinate system is constructed to transfer the end-link displacement of robot to that of the tool. A proposed GPI transform method, binocular vision technologies and a modified algorithm of line-line matching are utilized to calculate the positions of laser focus and weld seam, which makes the dynamic trajectory error between laser focus and weld seam can be calculated. The robot is finally commanded to move and decrease the trajectory error as soon as possible based on robot kinematics. Experimental results show that the method can effectively improve the trajectory accuracy of industrial robot for laser welding.

This paper proposed a design idea of a novel under-actuated finger mechanism, and designed the finger mechanism. The finger has no actuator in itself, is only driven by the other finger joints and object grasped. The finger is similar to a human finger and can be easily arranged in series to realize a finger with super under-actuation and high integration. It can be mounted in humanoid robot hand to make the hand obtain more DOFs with less actuators, and good grasping function of shape adaptation, decrease the requirement of control system. This paper analyzed the relationship between the grasping force of the finger and its design parameters, proposed the design principle of structure optimization of the finger. Based on the finger, a multi-fingered humanoid robot hand: TH-2 Hand has been designed. TH-2 Hand has many excellent features: high personification, super under-actuation and be very compact, easy to real-time control, small volume, light in weight, strong grasping function, etc.