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# Questions tagged [singularity]

To be used with questions regarding non-invertible matrices.

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### UR robots always have 2 parallel axes. Why not at a singularity?

I thought I understood the Jacobian and singularities pretty well, but then I was asked: UR robots (and others) have 2 joints that are always in parallel. Doesn't this put the robot at a singularity ...
• 883
139 views

### How to resolve singularity in six arm robot

I am using a six joint robotic arm (XArm 6). I would like to know what would be the best possible way to reduce singularities. I read that there are majorly three types of singularity for example ...
• 133
798 views

### 3R Planar robot arm singularity

To find the situation where singularity occurs, the determinant of the Jacobian is used. For the RRR planar robot with angles $q_1$, $q_2$, and $q_3$ and the length $L_1$, $L_2$, and $L_3$ as shown ...
2k views

### Null space of the Jacobian matrix for a robotic arm

I have doubts on how to find all the joint velocities that don't produce any linear velocity, so are in the Null space, when we are in a singular configuration. For example, suppose we have a 2R ...
• 479
1 vote
70 views

### Why does singularity condition for a serial manipulator never involve the first joint variable

In planar 2R the singularity condition involves the second joint variable. In spatial 3R, singularities involve second and third link lengths and angles. Why does the first joint parameter never ...
• 13
375 views

### Singularity problem at Inverse kinematic solver

I am struggling with this problem for days. I really hope that someone could give me a hint what the problem is. The robot consists of 5 axes. The first axis rotates around the z-axis and other 4 ...
• 324
139 views

### EKF singularity problem when measurement noise R is zero

my Extended kalman filter (EKF) program works well, my estimated state vector is same as real state vector when I give any positive definite number to measurement noise R. But I want to make ...
378 views

### Reachable Position with endeffector robotic arm

I have a 7 DOF robotic Arm. All the 7 Joints are rotational and have upper and lower joint angle limits. Now assume my end effector has a certain Pose $x = [X, Y, Z, a, b, c]$. My Question now is ...
• 133
295 views

### How to avoid matrix singularity in GraphSLAM

I am trying to implement GraphSLAM from Sebastian Thrun's paper, The GraphSLAM Algorithm with Applications to Large-Scale Mapping of Urban Structures. When I compute the inverse of my information ...
• 425
188 views

### Matrix is singular error in GraphSLAM

I have gone through The GraphSLAM Algorithm with Applications to Large-Scale Mapping of Urban Structures. I implemented the code for GraphSLAM. The fundamental formula of GraphSLAM is \mu = \Omega^...
• 425
1 vote
891 views

### Singular configurations of a 7-dof robotic arm

I want to check for singular configurations of a 7-dof robotic arm (RRRRRRR). I have found the geometric Jacobian and it is a 6x7 matrix. If my theoretical background is solid when the Jacobian loses ...
319 views

### Why are joint velocities very high near a singularity?

I am reading about singularities and I know that those are configurations which result in the same end-effector position and orientation. I also read that joint velocities get very high near that ...
• 35
1 vote
Suppose we have an $n$-DOF robot manipulator and let $q \in \mathbf{R}^n$ denotes a robot joint configuration. Then a singular configuration $q'$ is a configuration at which the Jacobian $J(q')$ does ...