A Novel Continuum Robot Using Twin-Pivot Compliant Joints: Design, Modeling, and Validation

Abstract

A twisting problem is identified from the central located flexible backbone continuum robot. Regarding this problem, a design solution is required to mechanically minimize this twisting angle along the backbone. Further, the error caused by the kinematic assumption of previous works is identified as well, which requires a kinematic solution to minimize. The scope of this paper is to introduce, describe and teste a novel design of continuum robot which has a twin-pivot compliant joint construction that minimizes the twisting around its axis. A kinematics model is introduced which can be applied to a wide range of twin-pivot construction with two pairs of cables per section design. And according to this model, the approach for minimising the kinematic error is developed. Furthermore, based on the geometry and material property of compliant joint, the work volumes for single/three-section continuum robot are presented, respectively. The kinematic analysis has been verified by a three-section prototype of continuum robot and adequate accuracy and repeatability tests carried out. And in the test, the system generates relatively small twisting angles when a range of end loads is applied at the end of the arm. Utilising the concept presented in this paper, it is possible to develop a continuum robot which can minimize the twisting angle and be accurately controlled. In this paper, a novel design of continuum robot which has a twin-pivot compliant joint construction that minimizes the twisting around its axis is introduced, described and tested. A kinematics model is introduced which can be applied to a wide range of twin-pivot construction with two pairs of cables per section design. Furthermore, based on the geometry and material property of compliant joint, the work volumes for single/three-section continuum robot are presented, respectively. Finally, the kinematic analysis has been verified by a three-section prototype of continuum and adequate accuracy and repeatability tests carried out.

Design of a cable-driven hyper-redundant robot with experimental validation

“…To this end, a cable-driven hyper-redundant robot is designed in this work. As discussed in Dong et al, 11 the twist problem should be carefully taken into consideration in the design of the hyper-redundant robot in order to keep its load/force capability. We utilize a kind of structure with two rotational joints in each section.…”

“…It was dexterous and could manipulate objects. Dong et al 11 developed a slender continuum-backbone robot composed of twin-pivot compliant joints, in which the whole section served as a universal joint. Xu and Simaan 9 developed a throat surgery system driven by Ni-Ti alloy tendons, which could conduct some dexterous operations such as suture.…”

“…[7][8][9] Many hyper-redundant robot mechanisms have been designed, which can be roughly classified into two categories: rigid-backbone robots and continuum-backbone robots. 10,11 The flexibility of rigid-backbone robots is determined by the number of joints and the length of links of the robots. For example, the active chord mechanism developed by Shigeo et al 12 which was composed of a large number of segments and joints was the pioneer work of rigid-backbone hyper-redundant robots.…”

A General Friction Model of Discrete Interactions for Tendon Actuated Dexterous Manipulators

“…They can be used as catheters for ablation [3,4], sheaths for irrigation/ adsorption or some miniature tools [5,6], endoscopic surgeries [7], or other steerable instruments [8] or robots [9,10]. The common use of the actuation is the cable or wire as the tendon, which is inserted into the conduit to interact with the flexible body of TA-DMs to generate the deflection.…”

“…Tendon-actuated dexterous manipulators (TA-DMs) can serve as end-effectors to provide great flexibility and maneuverability, which are widely used in a variety of fields [1], especially for minimally invasive surgeries in the confined anatomy [2][3][4][5][6][7][8][9][10]. They can be used as catheters for ablation [3,4], sheaths for irrigation/ adsorption or some miniature tools [5,6], endoscopic surgeries [7], or other steerable instruments [8] or robots [9,10].…”