Skip to main content Accessibility help

An on-line task modification method for singularity avoidance of robot manipulators

  • Changwu Qiu (a1), Qixin Cao (a2) and Shouhong Miao (a3)


In this paper, we present an on-line task modification method (OTMM) to realize singularity avoidance for nonredundant and redundant manipulators at the velocity level. The method introduces a correction vector, constructed from the task velocity and the singular vector corresponding to the minimum singular value, into the task velocity. The performance is simply affected by the choice of the lower limit of the minimum singular value and a scalar adjusting function, which is monotone with respect to the minimum singular value. The method makes unnecessary avoiding the singularity point by off-line path planning for nonredundant or redundant manipulators, and the effort to check whether the singularity is escapable for redundant manipulators. The simulation results show the effectiveness of the OTMM for on-line singularity avoidance in manipulator motion control.


Corresponding author

*Corresponding author. E-mail:


Hide All
1.Wampler, C. W., “Manipulator inverse kinematic solutions based on vector formulations and damped least-squares methods,” IEEE Trans. Sys. Man, Cybernetics, SMC-16 (1), 93101 (1986).
2.Nakamura, Y. and Hanafusa, H., “Inverse kinematic solutions with singularity robustness for robot manipulator control,” J. Dynamic Sys. Meas. Control 108, 163171 (1986).
3.Egeland, O., Sagli, J. R. and Spangelo, I., “A Damped Least-Squares Solution to Redundancy Resolution,” IEEE International Conference on Robotics and Automation, Sacramento, CA, (1991) pp. 945950.
4.Chiaverini, S., “Singularity-robust task-priority redundancy resolution for real-time kinematic control of robot manipulators,” IEEE Trans. Robot. Automation 13 (3), 398410 (1997).
5.Liu, T. S. and Tsay, S. Y., “Singularity of robotic kinematics: A differential motion approach,” Mech. Mach. Theory 25 (4), 439448 (1990).
6.Cheng, F. T., Hour, T. L. and Sun, Y. Y., “Study and resolution of singularities for a 6-DOF PUMA manipulator,” IEEE Trans. Sys. Man Cybernetics 27 (2), 165178 (1997).
7.Aboaf, E. W. and Paul, R. P., “Living with the Singularity of Robot Wrists,” IEEE International Conference on Robotics and Automation, Raleigh, North Carolina (1987), pp. 17131717.
8.Chiaverini, S. and Egeland, O., “A Solution to the Singularity Problem for Six-Joint Manipulators,” IEEE International Conference on Robot and Automation, Cincinnati, OH (1990), pp. 644649.
9.Duleba, I. and Sasiadek, J. Z., “Modified Jacobian Method of Transversal Passing through Singularities of Nonredundant Manipulators,” Robot. 20, 405415 (2002).
10.Mayorga, R. V., Wong, A. K. C. and Ma, K. S., “An efficient local approach for the path generation of robot manipulators,” J. Robot. Sys. 7 (1), 2355 (1990).
11.Mayorga, R. V. and Wong, A. K. C., “A Singularities Prevention Approach for Redundant Robot Manipulators,” IEEE International Conference on Robotics and Automation, Cincinnati, OH, (1990) 2 pp. 812817.
12.Muszyński, R. and Tchoń, K., “Singularities of nonredundant robot kinematics,” Int. J. Robot. Res. 16 (1), 6076 (1997).
13.Tchoń, K. and Muszyński, R., “Singular inverse kinematic problem for robotic manipulators: A normal form approach,” IEEE Trans. Robot. Automation 14 (1), 93104 (1998).
14.Bedrossian, N. S., “Classification of Singular Configurations for Redundant Manipulators,” IEEE International Conference on Robotics and Automation, New York (1990), pp. 818823.
15.Seng, J., O'Neil, K. A. and Chen, Y. C., “Escapability of Singular Configuration for Redundant Manipulators via Self-Motion,” IEEE/RSJ International Conference on Intelligent Robots and Systems, New York (1995), Part 3, pp. 7883.
16.Donelan, P. S., “Singularity-theoretic methods in robot kinematics,” Robot. 25, 641659 (2007).
17.Nakamura, Y., Hanafusa, H. and Yoshikawa, T., “Task priority based redundancy control of robot manipulators,” Int. J. Robot. Res. 6 (2), 315 (1987).
18.Cheng, F.-T. and Shih, M. S., “Multiple-goal priority considerations of redundant manipulators,” Robot. 15 (6), 675691 (1997).
19.Marani, G., Kim, J., Yuhl, J. and Chung, W. K., “A Real-Time Approach for Singularity Avoidance in Resolved Motion Rate Control of Robotic Manipulators,” IEEE International Conference on Robotics and Automation, Washington, DC (2002), pp. 19731978.
20.Tan, J., Xi, N. and Wang, Y., “A singularity-free motion control algorithm for robot manipulators—a hybrid system approach,” Automatica 40, 12391245 (2004).
21.Maciejewski, A. and KBein, C. A., “The singular value decomposition: Computation and applications to robotics,” Int. J. Robot. Res. 8 (6), 6379 (1989).
22.Maciejewski, A., “Real-Time SVD for the Control of Redundant Robotic Manipulators,” IEEE International Conference on Systems Engineering, Fairborn, OH (1989), pp. 549552.
23.Kirćanski, M., Kirćanshi, N., Leković, D. and Vukobratović, M., “An experimental study of resolved acceleration control of robots at singularities: Damped least-squares approach,” J. Dynamic Sys. Measurement Control 119, 97101 (1997).
24.O'Neil, K. A. and Chen, Y. C., “Instability of pseudoinverse acceleration control of redundant mechanisms,” IEEE International Conference on Robotics and Automation, San Francisco, CA (2000), pp. 25752582.



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed