Monday, September 1, 2008
Slowly we have to deal with the question of how to control our robot from afar. The computational functions like generation of joint trajectories and their realization in the controller have to be equipped with well defined interfaces and have to be able to communicate with each other. While this has been mostly solved for internal communication (using the TCP-IP connection), we are now working on the communication with the operator. Dealing with questions how the motion of the robot is being provided and controlled.
In a breadboard environment we evaluated the idea of directly reading the sensor information via the cRIO system. This would eliminate the need for additional servo boards at each leg and frees the CAN-Bus from some of its load. We also would have additional 16 analog channels available, which can for example be used to monitor the motor temperatures. Digital filters were implemented in the FPGA and the control code was ported to NI LabView were it runs in real-time at with a higher frequency.
So far the move seems to be a great success. And with the new singleboardRIO, it will become feasible to have the computation on board without adding a lot of additional weight.
The workshop has finished manufacturing of the new robot frame. Currently the composite casing is being built. Together they will provide a very stiff framework for the mechanical components and will also provide a dust-prove housing for the electronic components. With this step the mechanical redesign for the robot is finished and we can move on to integrate the specimen collecting mechanism. We also created a prototype for the textile cover of the legs. This was one of the critical issues, as we suspected that part of the fabric might jam the joint motion. However, preliminary test seemed promising.