|
Design and Implementation of a Visual Servoed Direct Drive SCARA Robot
This is the webpage for my graduation project in Sabanci University, Mechatronics Department. During my graduation project, I was a member of a four student team whose members designed and implemented a visual servoed direct drive SCARA Robot. The team members of the project were
Atakan Varol Ahmet Fatih Tabak Ugur Tumerdem Melih Fidanoglu
Click here for a nice pic of the team members.
Basically, the project was designing a two link SCARA manipulator using Yokogawa direct drive servo motors and integrating this robot with vision hardware. After we selected our project and started with the design phase, we realized that the project was more complicated then we thought before. Therefore, we divided the project into several parts:
In this part of the project, all the connections of the electrical and electronic parts are designed. This includes the design of the control cabinet (which has motor drivers, line filters, several fuses and relays etc.), driver-motor connections and the driver-DSP connections. There are a total of 24 pages of electrical drawings. All the cables in the electrical drawings are numbered in order to do electrical assembly and debugging easily.
The robot design was carried out in Solidworks 2004.
The Finite Element Analysis using CosmosWorks 2004 is also done for critical parts in order to do a safe design.
3) Computer Aided Manufacturing
The necessary G-codes to manufacture these parts are generated and the manufacturing procedures are simulated via SolidCam 2005. To produce these parts, Emco 155 and Maho CNC machines are used.
4) Mechanical and Electrical Assembly
Electrical assembly part consisted of building the control cabinet and the operator console, cabling, soldering connectors, producing PCB's.
In the mechanical assembly part; robot base, the direct drive motors, robot links and sensor towers are assembled together.
5) Control System Design and Implementation After the mechanical and electrical design and implementation is completed, the control system is designed. The control system design consists of creating the required analog torque reference signals for the base and elbow motor drivers and setting the logic signals required for the proper operation of the drivers. Then the motor drivers will create the required currents for the motors. Position and velocity control is done using digital independent joint PID controllers. For the control system hardware, the DSPACE DS1102 DSP Board is used. Two analog outputs, 10 Digital IO’s and 2 encoders of the DSPACE board are employed. The control program is written in ANSI-C and it is over 1200 lines. Furthermore, Graphical User Interfaces are created in DSPACE Control Desk
6) Vision System Design and Implementation
Our scenario was catching a thrown ball with the SCARA robot. We acquired images using a Philips Toucam Pro II - PCVC 830K camera at 30 fps. Using OPENCV libraries we tracked the ball, estimated the ball's time dependent trajectory and written this information to a file. Over Matlab-Mtrace we sent the trajectory information to the control software which generates the analog reference signal for direct drive robots.
For any questions regarding the project, please
feel free to contact me
|
