Quanser's Mobile Robot Control Framework

Quanser’s Mobile Robot Control Framework (QMRCF) is undergoing extensive development. The software framework of QMRCF, based on QuaRC, includes three blocksets: Interface, Application, and Image processing. These blocksets allow a user to build a model-based controller in Simulink™ and to generate suitable code for Gumstix on Windows or QNX for preliminary testing. QMRCF has been tested on Qbot to implement teleoperation with force feedback and autonomous navigation with obstacle avoidance. The goal of teleoperation application is to remotely control a mobile robot with a joystick. The following video clip shows a teleoperation where an operator was driving Qbot using a joystick and the image feedback from Qbot was displayed on the host Windows PC.

An application of force-feedback in teleoperation is demonstrated in the following video clip. The force-feedback is associated with Qbot's bump sensors. The operator feels the reaction force on a COTS joystick while the bump sensor collides with any objects.

The navigation application defines a target point (p₂) with respect to the initial position of the robot (p₀) using an occupancy map (see Fig. 1). White pixels of the occupancy map indicate obstacles whereas black pixels indicate empty space.

Fig. 1

The navigation algorithm generates motion commands according to the current position of the robot and the target. The robot starts at p₀ and tries to avoid dynamic obstacle at point p₁ (see the following video clip) and finally, reaches the target position at p₂. This method maintains a short-term memory of the previously bumped obstacle's position. The robot, first, moves opposite to the obstacle and then rotates and moves forward to avoid the obstacle. Fig. 1 shows robot’s trajectory from p₀ to p₂.

Further development on QMRCF will include mapping and multi-agent applications.

Rajib