# Questions tagged [kinematics]

Kinematics is the branch of mechanics dealing with the motion of points and objects.

330 questions
Filter by
Sorted by
Tagged with
16 views

### Classical DH and Euler angles parametrization

Let DH convention is carried out as $$A_i = \text{Rot}_{z,\theta_i}\text{Trans}_{z,d_i}\text{Trans}_{x,a_i}\text{Rot}_{x,\alpha_i}$$ This is the classical DH method stated in Spong's book. The ...
• 2,347
71 views

### Redundancy and Null space projection

I'm reading "Theory of Robot Control" by Carlos Canudas Wit, Bruno Siciliano, Georges Bastin. In Task space control chapter, exploiting the redundancy by means of null space as shown below ...
• 2,347
9 views

### Estimating the bycycle model using point sets from consucutive frames

I have two sets of points from two consecutive frames (restored from a video). The data represent points on the surface of a single-vehicle moving between frames. Points are in 3D and are assumed not ...
• 101
47 views

### Body angle of a centre-articulated robot

Wondering if anyone can help me out with this one, or point me in the right direction. I am working on a centre-articulated robot, which is steered via a push-pull chain drive. The chain drive is ...
1 vote
70 views

### How to get transform between two fixed frames using a camera

In my task, I have two manipulators: one 6 dof robot (Manipulator 2 as shown in attached link picture), and one passive arm (Manipulator 1 as shown in attached link picture). Both the frames 1 and 2 ...
• 11
63 views

### What is the consquence of Gimbal lock?

I'm learning about Gimbal lock and I understand the reason why that happened. But I don't understand why that is a big deal because it only affect this rotation. After this rotation finished, we have ...
22 views

### Robot increases in length, trying to keep robotic along previous position trajectory

Sorry for the confusing title, this seems to be a difficult problem to concisely describe. I am working on a 50-DOF (yes, 50) robot that is comprised of "elbow macaroni" links that rotate ...
• 1
1 vote
121 views

### How to solve this basic dynamics/inverse kinematics problem

Suppose I have a 6-DOF robot arm with revolute joints whose tooltip is at some position $\bf{r_0}$ and I want to move it through some trajectory ${\bf r}(t)$. For simplicity, assume there are just 2 ...
• 156
20 views

### VR: is it possible to calculate hand position relative to head based off these known orientations and lengths?

If we have 3, 9DoF IMUs for absolute orientation data on the: wrist upper arm forehead and we know the length of the: wrist upper arm shoulder to base of neck neck and we also know the global ...
51 views

### Inverse kinematics for 2DOF robotic arm in 3D

i am trying to find the inverse kinematics for quadrotor with 2Dof robotic arm, which has first joint rotation axis perpendicular with second joint. So, for the inverse kinematics i use two equations ...
39 views

### Problem with Inverse Kinematics Solver (Jacobian Inverse Method)

I am trying to create an inverse kinematics solver for my 4-dof (all revolute joints) robot using the inverse Jacobian Method. However, it does not seem to be working as the distance between target ...
25 views

### Defining the specifications required by a 6DOF robot to impose a harmonic sinusoidal motion

Perhaps a bit of a simple question, but since I don't have a background in robotics/engineering, then I imagine this would be the perfect place to ask such a question. I am buying a 6-DOF Stewart ...
81 views

• 111
57 views

### control of a rod attached to a motor

I have a 76 cm, aluminum rod, attached to the shaft of a 12v DC banebot motor. The rod is hanging vertically initially, and rotates in the vertical plane. The task is to control the rod to make it ...
• 111
62 views

### Robot differential drive wheel speed

I would like to build a small robot. The robot will have 4 independent motors, one for each wheel. It will have a rear axle fixed and the front axle will be freely pivoting around its center, somewhat ...
• 101
23 views

### Trajectory optimal for quadcopter

I have defined a quadcopter that I control with a PID controller. The dynamics that define it are such. $T=mg+m\ddot{z}$ $\theta=\frac{\ddot{x}}{-9.82}$ $\phi=\frac{\ddot{y}}{9.82}$ As you can see I ...
70 views

### Holonomic constraints on an upright wheel

A wheel moving in free space has the six degrees of freedom of a rigid body. If we constrain it to be upright on a plane and to roll without slipping, how many holonomic and nonholonomic constraints ...
235 views

### In MuJoCo why do some XML files have objects fall to the ground while others are just fixed above the ground?

Why do some models, or objects in a MuJoCo XML script fall to the floor while others don't? In the models files that come with the MuJoCo zip, the robot arm (arm26) does not fall to the ground while ...
• 113
75 views

### Confusion about Gimbal lock

I am trying to understand exactly what is happening when Gimbal lock occurs. I have read many explanations now which provide the high-level idea, in that Gimbal lock occurs when two axes are aligned ...
49 views

### Forward Kinematics for articulated manipulator not giving right answer

I calculated the forward kinematics for an articulated manipulator robot in ROS, but I am not getting the right answer. Here is the diagram for the robot configuration I used- When Q1,Q2,and Q3 are ...
43 views

### Trajectory following of 3-wheel omnidirectional robot

I created a three-wheeled omnidirectional robot on omni-wheels, there is also a program in which I can plot a trajectory when plotting a trajectory, such data are obtained (X, Y, Tangent X, Tangent Y, ...
101 views

### What does RR stand for in RR-manipulator?

I have memorized RR-manipulator as having 2 arms from Google images but "arm" isn't spelled with "R". I also noticed that RRR-manipulator has 3 links. Does R stand for revolute?
43 views

### How to calculate DH parameters for Higher Pair?

I am trying to build a robot which is having Bevel Gears connecting two links. I want to calculate DH parameters, but i am stuck with this bevel gear as when the joint rotates both angle and ...
1 vote
56 views

• 179
1 vote
253 views

### Calculate Torques & Forces From Jacobian Matrix

Dear Robotics Stack Exchange, I am trying to calculate the torques and forces for a 2DOF robot. I’m used the partial differentiation method to find the Jacobian matrix. I managed to find the ...
• 113
1 vote