Design and Development of a Radiation Protection Assistant Robot

Abstract

Robots are playing quite a useful role in many industries. In nuclear industry, robots protect radiation workers from receiving radiation doses while working in highly active areas. They also improve the quality of work and demonstrate profitability in nuclear industry. The aim of this project was to design and develop a Radiation Protection Assistant Robot (RPAR) for assisting radiation workers in a radioactive environment for routine work as well as in emergency situation. During an emergency situation, where higher doses are likely to be received, RPAR can be used effectively to perform various tasks, such as radiation mapping, sampling and handling radioactive waste/materials. To accomplish these tasks a mobile robot having 4 Degree-Of-Freedom (DOF) articulated robotic arm was designed and developed using locally available components and indigenous resources. The mechanical segments, i.e. gripper, wrist, elbow, shoulder and waist were developed at Pakistan Institute of Engineering & Applied Sciences (PIEAS) and Pakistan Institute of Nuclear Science & Technology (PINSTECH). The main platform was developed to carry on-board computer, rechargeable battery, controlling electrical and electronics modules/circuits. The electronic modules have been developed using components available in local market. These modules include H-bridge, relay logic, parallel port interface and limit switch modules. Control panel and remote console are developed to control and operate the RPAR. An embedded controller card was also developed to determine the positions of various links of RPAR. RPAR weighs 55.6 kg. It is powered by a 12 V DC rechargeable dry battery. Its maximum payload capacity and reach are 2.1 kg and 1.04 m, respectively. It can be controlled by a wired remote control or an off-board PC via wireless Ethernet. Three Software namely RPARSOFT, RPAR-DEMO and SEDAS were designed and developed using Visual Basic 6.0. RPARSOFT was developed to operate the RPAR from the keyboard of an off-board computer. The RPAR- DEMO was developed to self check the electrical and electronic modules of RPAR, whereas, SEDAS was designed for the embedded controller card to determine the real time position of wrist, elbow, shoulder and waist of RPAR. Kinematics studies, Dynamics analysis, manipulator Jacobian and work space analyses were performed to study the performance and range of the robot. Repeatability range and payload capacity of RPAR was measured. Radiation hardening study has also been carried out to check the stability and reliability of the commercial components in the field of gamma radiation. The modules were found working satisfactorily before and after irradiating them up to a dose of 9 Sv. The objectives have been achieved successfully.