Accuracy of robots is an important facet in an industrial setting. In this paper, we present a novel kinematic calibration methodology. Traditional calibration techniques require an external metrology device. Unlike those, the presented product here is highly practical in that it does not require a metrology device. The kinematic calibration model is formulated by making use of the robot itself as a metrology device to measure the geometry of a known artifact. The optimal parameters/characteristics of the model are identified using a Particle Swarm Optimization (PSO) technique. Our experimental results show that this new approach provides results comparable to those generated using spatial information provided by a Coordinate Measurement Machine (CMM). Using this new approach (GageCAL), the Yaskawa Motoman “MHS-Hi” robot is calibrated. Our experimental testing also indicates that this methodology can be extended to a wide variety of anthropomorphic robots.

Robotic manipulators with joints that are capable of precisely monitoring the instantaneous torque are currently being used in collaborative robots. These robots are safe to work alongside human beings, and execute tasks that rely on force control. A spring is placed in series inside a robotic joint actuator deflects as per the torque transfer; this information is then used by the controller to control the robot as needed. Based on this key idea, a new device is invented wherein the spring stiffness can be servo-controlled. A mathematical model of this device is presented here with its potential applications that contributes to a safe work environment.