Hi all,

I am a student and I am working on a surgical eye robot which utilises a remote centre of motion mechanism (RCM). I have found the forward kinematics for it using the DH method and another method. I have also found the Jacobian velocity matrix for it. However, my Jacobian seems a bit off and I am looking to validate it and the forward kinematic using RST. I have exported the CAD model as XML and created an slx file for it. The robot composes of multiple joints. However, in reality, only 4 joints are actuation joints, the rest are closed loop joints that reduce the robots DOF to 1 or 2 DOF (pitch and translation).

I have set up the robots and actuated it fine using a constant block connected a degree to radians block which is then connected to the robot, which is connected to a MATLAB function script which is then connected to a display to show me the homogenous matrix.

I am now at the stage where I am looking to connect a GetTransform block in order to retrieve the forward kinematic. Below is the way I am connecting the blocks. My apologies since I am using a different computer and can’t screenshot my layout.

3 Sine blocks and a constant block connected to the robots (I have made the robots connection and blocks a subsystem). From the robot subsystem, it’s connected to a mux that takes 4 inputs. The mux is connected to the GetTransform block. The GetTransform block is connected to a Coordinate Transformation Conversion block which is then connected to a scope.

All of my setup seems fine. However, I am getting an error that says the input is a vector of 4 whereas the outputs requires 11. I know this is due to the joints block where I have set up 4 of them to sense the postion and computed the torque automatically and I have 11 joints in total. When I add an additional Simulink to PS and PS to simulink to another joint, I get an error like this: "The input is a vector of 5 whereas the outputs requires 11". As mentioned, only 4 of the joints are actuating joints and joints that I need to find the forward kinematic for. How can I fix this issue without adding more joints to sense the position?

My second question is rather simple. I am using 3R1P configuration. I know I can get a constant block connected to a degrees to radians block to control the revolute arm of the robot. What is a similar setup I can use to move the prismatic joints?

Thank you so much for the help in advance!Hi all,

I am a student and I am working on a surgical eye robot which utilises a remote centre of motion mechanism (RCM). I have found the forward kinematics for it using the DH method and another method. I have also found the Jacobian velocity matrix for it. However, my Jacobian seems a bit off and I am looking to validate it and the forward kinematic using RST. I have exported the CAD model as XML and created an slx file for it. The robot composes of multiple joints. However, in reality, only 4 joints are actuation joints, the rest are closed loop joints that reduce the robots DOF to 1 or 2 DOF (pitch and translation).

I have set up the robots and actuated it fine using a constant block connected a degree to radians block which is then connected to the robot, which is connected to a MATLAB function script which is then connected to a display to show me the homogenous matrix.

I am now at the stage where I am looking to connect a GetTransform block in order to retrieve the forward kinematic. Below is the way I am connecting the blocks. My apologies since I am using a different computer and can’t screenshot my layout.

3 Sine blocks and a constant block connected to the robots (I have made the robots connection and blocks a subsystem). From the robot subsystem, it’s connected to a mux that takes 4 inputs. The mux is connected to the GetTransform block. The GetTransform block is connected to a Coordinate Transformation Conversion block which is then connected to a scope.

All of my setup seems fine. However, I am getting an error that says the input is a vector of 4 whereas the outputs requires 11. I know this is due to the joints block where I have set up 4 of them to sense the postion and computed the torque automatically and I have 11 joints in total. When I add an additional Simulink to PS and PS to simulink to another joint, I get an error like this: "The input is a vector of 5 whereas the outputs requires 11". As mentioned, only 4 of the joints are actuating joints and joints that I need to find the forward kinematic for. How can I fix this issue without adding more joints to sense the position?

My second question is rather simple. I am using 3R1P configuration. I know I can get a constant block connected to a degrees to radians block to control the revolute arm of the robot. What is a similar setup I can use to move the prismatic joints?

Thank you so much for the help in advance! Hi all,

I am a student and I am working on a surgical eye robot which utilises a remote centre of motion mechanism (RCM). I have found the forward kinematics for it using the DH method and another method. I have also found the Jacobian velocity matrix for it. However, my Jacobian seems a bit off and I am looking to validate it and the forward kinematic using RST. I have exported the CAD model as XML and created an slx file for it. The robot composes of multiple joints. However, in reality, only 4 joints are actuation joints, the rest are closed loop joints that reduce the robots DOF to 1 or 2 DOF (pitch and translation).

I have set up the robots and actuated it fine using a constant block connected a degree to radians block which is then connected to the robot, which is connected to a MATLAB function script which is then connected to a display to show me the homogenous matrix.

I am now at the stage where I am looking to connect a GetTransform block in order to retrieve the forward kinematic. Below is the way I am connecting the blocks. My apologies since I am using a different computer and can’t screenshot my layout.

3 Sine blocks and a constant block connected to the robots (I have made the robots connection and blocks a subsystem). From the robot subsystem, it’s connected to a mux that takes 4 inputs. The mux is connected to the GetTransform block. The GetTransform block is connected to a Coordinate Transformation Conversion block which is then connected to a scope.

All of my setup seems fine. However, I am getting an error that says the input is a vector of 4 whereas the outputs requires 11. I know this is due to the joints block where I have set up 4 of them to sense the postion and computed the torque automatically and I have 11 joints in total. When I add an additional Simulink to PS and PS to simulink to another joint, I get an error like this: "The input is a vector of 5 whereas the outputs requires 11". As mentioned, only 4 of the joints are actuating joints and joints that I need to find the forward kinematic for. How can I fix this issue without adding more joints to sense the position?

My second question is rather simple. I am using 3R1P configuration. I know I can get a constant block connected to a degrees to radians block to control the revolute arm of the robot. What is a similar setup I can use to move the prismatic joints?

Thank you so much for the help in advance! robotic, robotic system toolbox, matlab, forward kinematic, jacobian, simulink, simscape, setup MATLAB Answers — New Questions

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