jdios
  • Member for 3 years, 4 months
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What's the difference between Pose Measurement and Position Measurement?
6 votes

what you are looking for is written in the paper. Position refers only to x,y,z translational measurements while pose means position and orientation.

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Understanding Impedance Control
Accepted answer
3 votes

Yes, it is the same, $F$ should be the same as $F_{ext}$. And $F$ comes from a sensor or an estimation, in general from a force sensor. The diagram seems correct and you may have $F$ and $F_{ext}$ ...

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Why do I need impedance control?
3 votes

Imagine that you hold a position very stiff in your arm. You are holding your muscles tight to keep that position and hold it very tightly. Then you walk to move your arm without moving your arm with ...

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smoothing the robot poses inbetween two known poses
3 votes

You could try to use a bezier curve (https://en.wikipedia.org/wiki/B%C3%A9zier_curve) to interpolate with a curve and via points between A and B'. Also, is this a mobile robot or a robot arm? Do you ...

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how to use ROS navigation stack with 4 wheeled robots
2 votes

Yes there is. You need to develop or look for the developed equations of velocities that provides the math that transform from the x y theta velocities to the velocities on each of the motors that you ...

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Concatenate Jacobian matrices
1 votes

Unfortunately is not as straightforward as multiplying them. The Jacobian of B is considering that the first body is fixed to the plane. You would need to add the velocity at that point, which is the ...

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Compute how well a laser scan matches or overlaps with its environment given a map of the environment and location of the robot is known
1 votes

You should look into localization algorithms. A good source is the book Probabilistic Robotics - W. Burgard, D. Fox and S. Thrun. If you just want to compute somehow how well it agrees you could try ...

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Questions about time derivative of jacobian matrix
1 votes

If you use the partial differentiation you can get to that expression as \begin{align} \frac{dJ}{dt} &= \frac{\partial J}{\partial q}\frac{\partial q}{\partial t} \\ \frac{dJ}{dt} &= \frac{\...

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Robots and RTOS
1 votes

The answer is yes, for example many robot computers are based on the linux real-time kernels to handle the real-time constraints. For small robots for teaching like the turtlebot uses a raspberry pi ...

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When not to use pseudoinverse?
1 votes

Short answer: you can use it. Long answer: Depend on your case, but I have seen many papers where they use the pseudoinverse of the non-square Jacobian matrix. The rectangular Jacobian matrix opens ...

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Simulator for NEMA17 (stepper motor) and A4988 (stepper motor driver) along with Arduino
1 votes

You can do that in Proteus. You can simulate a stepper motor there, but only to see the motion, it is not possible to simulate the speed, inertia, and mechanical response.

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How do you create a log of create_autonomy published messages?
1 votes

, there is a standard tool for that: rosbag, it can record any message on the ROS network, you can take a look at the following link to see its usage http://wiki.ros.org/rosbag

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Dynamic models of parallel robots in the form of multi-mass systems with stiffness coefficients
1 votes

Yes it is possible. You can look at the following paper Stiffness Analysis and Comparison of 3-PPR Planar Parallel Manipulators With Actuation Compliance Guanglei Wu , Shaoping Bai , Jørgen A. ...

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Dynamixels (AX-12A) no longer detected after id change
Accepted answer
1 votes

Try a for loop with all possible ids until it is detected.

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Articulated configuration
1 votes

Seems that the book has an error. You are right, they should correct that. In the drawing it can be seen that those two z-axis are indeed parallel. I recommend that you considered them parallel and ...

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Sensing torque of stepper motor
1 votes

Sensing the torque in a stepper motor is not a straightforward task. A method named Field Oriented Control is used to control the torque in a Stepper motor and several companies supply stepper motors ...

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Can knowledge of robot's dynamics help in motion planning?
1 votes

Yes it helps but it definitely adds complexity to the planners. Depending on the wheel configuration, how many wheels, the mass of the robot, the moments of inertia, same as the mass of the wheels, ...

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Effiecient computation of coriollis matrix
1 votes

You can try to do some optimization of your computations. Things you can try Simplify the expression in your symbolic computation program. In matlab for example this is done with the 'simplify' ...

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Calculate the inertia matrix of complex robotic mechanism
1 votes

It is approximate and very accurate as long as the material properties are well defined. Many methods are combined to get it. Moment of inertia, parallel axes, mass distribution, etc etc. ...

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Force controller with feedback issues
1 votes

You can try the following. Set an admittance you want as $ F_e = m_d \ddot q + c_d \dot q$ then, you can solve for $q$ as the velocity reference $q_r = \frac{F_e - m_d \ddot q_r}{c_d}$ and ...

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Dynamic model using identification for control
1 votes

Given that you have your forward kinematics already, you can formulate the dynamic model with the two methods mentioned in the answer by Ababu. Then you can put estimates of your robot parameters (...

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How to deal with current spikes due to fast direction-switching motor commands?
1 votes

You can try to put a capacitor in the motor terminal. Very close to the motor.

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Reliably enabling/disabling a PID loop via FSM in a microcontroller
0 votes

You could probably just have the FSM outside the interrupt routine since it is not a time critical function of your system as a PID is. Then in the FSM can update an enable or disable variable that ...

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ROS Navigation stack with Omni-wheel robot
0 votes

It really depends on your robot kinematics (where is the location of the wheels in the robot frame and what type of wheels it have). There are a lot of resources online to get it from the ...

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Torque calculation for a shaft end effector
0 votes

I will try share some light in this matter. Your understanding of the torque is only valid when the distance vector is not parallel with the axis of rotation (in your case is parallel). In your case ...

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Model of two link rigid manipulator
0 votes

the model would be different because of the location of the center of mass of the links, so maybe in one model is just the total length d while in others might only be d/2. To calculate the center ...

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How to calculate heading more accurately using dead wheels?
0 votes

You need to develop the differential kinematics of this mobile platform for all of the wheels then you can combine it in your model. Other way to do it is to implement an observer based technique to ...

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How to compute associated (partial) Jacobian matrix for each joint of a serial manipulator?
0 votes

I believe you refer to first order partial derivatives. It is as easy as to take the forward kinematics from T0n , where n is the point to where you want to take the partial jacobian matrix and do the ...

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What is the best way to simulate a robotic arm?
0 votes

Try to use V-REP, it is very straighforward to use and got a MATLAB and ROS interface. Is usable in WIndows, MAC and Linux.

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Very high value readings for light bumpers
0 votes

I can only think there is something wrong with the firmware or the hardware. Maybe you can try to reupload the firmware or update it.

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