Weijun Zhang

The optimization scheme for EOD robot based on supervising control architecture

The explosive ordnance disposal task in constrained environments needs high efficiency of operation and adaptability to avoid obstacles. In this paper, a redundant manipulator is presented to enhance the manipulability, the mechanical and control system is introduced and supervised control framework is adopted to deal with approaching and grasping task in confined workspace. The manual configuration control is presented and the concept of Collision Threat Index (CTI) base on infra-red sensor information is defined for optimization. The optimization scheme of configuration adjustment for collision avoidance is adopted and the algorithm is intuitive and is suitable for real time control. A series of experiments of EOD task in under-vehicle environment have been done and the results show the effectiveness of presented approach.

Research on Novel Wire Driving Robot Manipulator for Local Industrial Production Line

The research on robot manipulator is not new topic. However, it is still not easy to localize the manipulator in present writers region nowadays. The reason partly comes from the difficulty of reducing the manufacturing cost as well as keeping high displacement accuracy. This paper describes the research on a novel wire driving robot manipulator as a try to substitute low cost, high accuracy and large payload ability localized manipulator for the common production. Generally speaking, as to the design method of robot arms, especially of large used industrial robot manipulators, installing the driving components -such as the electric motors, transmissions and so on -directly just nearby the relative joints, is still normal. The trial model described in this paper is a 4-degree-of-freedom robot manipulator for industrial purpose, which is designed with wire driving mechanism including novel wire tensioner so that the structure becomes compact and simple, the whole weight is dropped, at the same time, the output power to do work and the displacement accuracy are increased relatively. We describe the control system and carry out several experiments to verify performance of this first trial model and expect that could be put into large practical use in future.

Virtual realization of automatic stair-climbing motion by leg-wheeled hybrid mobile robot

We have already researched and realized some of the automatic control motions for eight leg-wheels hybrid stair climbing mobile robot, which was developed for aged and disabled person helping them moving freely in structured environment. However, the implementation of such control algorithm has to be carefully checked before carrying person on. In this paper, we discuss the efficiency of the control algorithm for stair climbing, slope, complex steps and simple obstacles; also, examine the reliability and safety based on the virtual platform built in OpenGL.

Design of cooling system for inspection manipulator and analysis based on experiment

Purpose – This paper aims to present a different cooling method (water cooling) to protect all the mechanical/electrical components for Tokamak in-vessel inspection manipulator. The method is demonstrated effective through high temperature experiment, which provides an economical and robust approach for manipulators to work normally under high temperature. Design/methodology/approach – The design of cooling system uses spiral copper tube structure, which is versatile for all types of key components of manipulator, including motors, encoders, drives and vision systems. Besides, temperature sensors are set at different positions of the manipulator to display temperature data to construct a close-loop feedback control system with cooling components. Findings – The cooling system for the whole inspection manipulator working under high temperature is effective. Using insulation material such as rubber foam as component coating can significantly reduce the environmental heat transferred to cooling system. Origi...

An automatic collision avoidance approach for remote control of redundant manipulator

In this paper, a modeling, planning and remote control of a redundant manipulator for a semi-structured ldquounder vehiclerdquo environment is investigated. The geometric characteristic is abstracted by the distance laser sensory information and collision danger is measured in real time to activate the self-motion of reshaping the configuration. To make a real time solution, a intuitive collision avoidance method is presented for planar manipulator. Incorporating the algorithm with the supervisory control framework, a dynamic trajectory planning algorithm is presented for rapidness requirement of bomb disposal tasks. The simulation and experiments prove the effectiveness of presented method.

Design and prototyping a cable-driven multi-stage telescopic arm for mobile surveillance robots

Telescopic mechanism has lots of merits and is used in devices and equipment long before the appearance of robots. This paper explores the merits of telescopic mechanism and designs a cable-driven multi-stage telescopic arm with only one actuated degree of freedom (DOF) for mobile surveillance robots. We use pulleys and cables as the transmission system and use a DC motor together with harmonic drive as the actuation system. We analyze the integration of pulleys and cables to reduce cost and carry out numerical analysis by simulation and prototyping. The results show that our arm is fast, portable, stable and has low cost. We expect it to be widely employed for camera lifting tasks in mobile surveillance systems without significantly increasing costs. We also expect its general usage as an arm to support various end-effectors.

An improved rate-monotonic scheduler and a real-time open control platform for robotic control algorithm verification

The verification of new intelligent robotic control algorithm not only requires the correction of computation but also satisfies the timing constraints. In this paper, an open real-time control environment is designed and implemented for robotic control algorithm verification. With Windows NTs real time extension RTX, the PC based control system will have good real-time performance for new control algorithm research. The software structure and the task scheduling approach are described in detail and the software comprises of real-time motion control & trajectory planning process, the uses operating interface process and the inter-process communication module. Considering the uncertainty in computation time of complex intelligent algorithms in robotic systems, the running time of the algorithm is monitored online and an improved rate-monotonic scheduler is presented for schedulability verification. To prove the effectiveness of the open real-time control environment and task scheduler, two examples, a direct driven air-bearing stage for IC packaging and a SCARA type robot for assembly, are introduced. The control performance and task scheduling results show that the open real time control environment and new scheduler are successful in complex control algorithm research and timing verification.

Design and qualification tests of a robotic joint module for tokamak in-vessel manipulator use

Purpose n n n n nThis paper aims to present the design and a prototype experiment of a robotic joint module for tokamak in-vessel manipulator-related research; the results will promote the adaptation of current in-vessel inspection manipulator to achieve full tokamak in-vessel environment compatibility. n n n n nDesign/methodology/approach n n n n nA flexible metallic bellow-enclosed working chamber is used to protect the main servo drive components, the active cooling method for high temperature protection and the servo control structure simplification for high radiation endurance. A joint module prototype is manufactured and tested under a similar in-vessel environmental condition for extreme condition protection validation and basic servo control ability evaluation. n n n n nFindings n n n n nThe joint module prototype successfully survived the similar in-vessel environment tests and proved good mobility via closed-loop servo control. A conceptual design of a serial linkage manipulator with joint module structure is proposed for future in-vessel inspection manipulator development. n n n n nOriginality/value n n n n nThe proposed joint module uses common industrial servo components to achieve its full extreme in-vessel environment compatibility. Different from traditional metallic bellow application in a vacuum environment to produce a linear movement result, the proposed joint module aims to achieve rotating movement directly from the metallic bellow structure, thereby reducing the joint structure space requirement, simplifying the vacuum environment movement transmission structure and increasing the vacuum environment compatibility degree.

Design of novel terrain adaptable cascading wheeled mobile platform with passive planetary swing structure

This paper describes the design principle and detailed considerations for a new developed wheel type mobile platform. The vehicle is designed as one of the choices for real practical use such as rescue or public security purpose. The vehicle utilizes eight big wheels and installs them into two side rows. All the wheels are densely cascading assembled and are nearly half overlapping with each other. A new planetary swing wheel structure is utilized in this vehicle, as a result of which, the necessary actuators for 8 active wheels are reduced to four. The planetary swing structure adjusts the relative posture to the vehicle chassis passively and automatically, according to the coming terrain situation, without using other mechanical swing structures or motion assistant mechanism. Mechanical discussion and analysis, such as the varieties of planetary swing structure, wheel distribution, are given in this paper. Also, in the later part, experimental tests are carried out to exam the traversing effect.

Structural analysis of steel-cable-driven multi-joint robot manipulator

We have been researching robot manipulators with steel-cable-driven structure. The reason of using such are to implement serial manipulators interesting performance such as low cost, large payload ability as well as light self-weight, and also flexible features. While, on the other hand, the normal ring winding structure remains disadvantage in motion coupling, also complex in control. In this paper, we first propose a novel planetary 8-shape cable winding structure in n-DOF robot manipulator, and then discuss its characteristics, such as the geometry, the kinematics, and the force/torque transmission mechanism. The later chapter of the paper reports a trial 5-DOF model with basic experiments to verify the above theoretical analysis and simulation. Hopefully, such structure should have the possibility to expanding its application into industry, serial manipulator, snake-like structure, for instance.