Real-time motion generation for tendon-driven continuum robots requires accurate modeling of nonuniform bending and whole-body collision avoidance. This paper presents a unified actuation-space framework for planar multi-segment tendon-driven continuum robots. An energy-based variable-curvature model captures spatially varying tendon spacing and bending stiffness and provides analytical Jacobians for differential inverse kinematics and safety monitoring. A multipoint CBF-QP enforces backbone clearance under obstacle motion and actuation-velocity bounds, while its decision dimension depends only on the number of independently actuated segments. The model closely agrees with GVS references, with a maximum curvature error of 5.223×10−2m−1. Over 100 MuJoCo trials, the proposed method achieves collision-free success rates of 96% and 100% in static and dynamic scenarios, respectively, compared with approximately 60% and 80% without CBF constraints. Hole-traversal tests further demonstrate safe motion in constrained environments. With 600 backbone monitoring points, the mean control-step time is 6.66 ms, demonstrating real-time whole-body safe motion generation.
Figures & tables
Fig. 1: Real-time whole-body safe motion generation for continuum robots. (A) Robot and kinematics. (B) Whole-body collision avoidance. (C) Real-time CBF-QP control framework.
Parameter
Symbol
Value or profile
Unit
Number of segments
N
3
–
Total backbone length
L
0.30
m
Segment lengths
Li
[0.12,0.10,0.08]
m
Young’s moduli
Ei
[6.0,7.0,5.5]
MPa
Diameter profile
D(s)
6.4×10−3(1−0.5s/L)
m
Second moment of area
I(s)
πD4(s)/64
m4
TABLE I: Simulation Parameters
Fig. 2: Kinematic validation against GVS: shape comparison and segment-wise curvature errors.
Fig. 3: Sim-to-sim validation of real-time whole-body safe motion generation in MuJoCo: static and dynamic obstacle avoidance and hole traversal.
CBF sampling points
Δs[m]
Mean control-step time (ms)
100
0.00758
1.1692
200
0.00377
1.9870
300
0.00251
2.9671
400
0.00188
3.6831
500
0.00150
5.0753
600
0.00125
6.6641
TABLE II: CBF Sampling Density and Computational Cost