Tendon-sheath actuators (TSAs), similar to Bowden cable-based series elastic actuators (SEAs), have a wide range of applications in robots. However, when applying them to manipulators, force sensors cannot be mounted due to limited space. Therefore, this paper proposes a new method for compliant control based on a dual encoder, and the existing transmission model was improved by considering the joint torque. To validate the proposed method, experimental setups composed of a motor, a tendonsheath component, a robotic joint, force sensors, and position sensors are established. The transmission processes are interpreted clearly through a position control mode. Parameter identifications without external disturbance force are conducted to acquire the ideal transmission model, and the error value between the experiment data and the fitted curve is measured. The availability of the presented scheme is verified by compliant control experiments, including collision detection and hand guiding, and the frequency characteristics of the actuator are analyzed. The results show that the function can be realized without force and torque sensors during the whole process. INDEX TERMS Tendon-sheath actuators, robotic manipulator, compliant control, position transmission model, parameter identifications, series elastic actuators, transmission characteristic.

The double tendon-sheath drive system is widely used in the design of surgical robots and search and rescue robots because of its simplicity, dexterity, and long-distance transmission. We are attempting to apply it to manipulators, wherenon-linear characteristics such as gaps, hysteresis, etc., due to friction between the contact surfaces of the tendon sheath and the flexibility of the rope, are the main difficulties in controlling such manipulators. Most of the existing compensation control methods applicable to double tendon-sheath actuators are offline compensation methods that do not require output feedback, but when the system’s motion and configuration changes, it cannot adapt to the drastic changes in the transmission characteristics. Depending on the transmission system, the robotic arm, changes at any time during the working process, and the force sensors and torque sensors that cannot be applied to the joints of the robot, so a real-time position compensation control method based on flexible cable deformation is proposed. A double tendon-sheath transmission model is established, a double tendon-sheath torque transmission model under any load condition is derived, and a semi-physical simulation experimental platform composed of a motor, a double tendon-sheath transmission system and a single articulated arm is established to verify the transfer model. Through the signal feedback of the end encoder, a real-time closed-loop feedback system was established, thus that the system can still achieve the output to follow the desired torque trajectory under the external interference.

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The topology optimization method is adopted to realize the weight reduction of the mechanical arm under the rigidity condition. The typical configuration and load conditions of the manipulator are analyzed. The stiffness mass model of the part is established by the finite element analysis method, and the topology optimization of the part is carried out. On this basis, the optimization of the manipulator system is completed. The optimized art quality is reduced by 6.2% compared with the original model, and the stiffness meets the standard requirements. The method of combining virtual joint method with working space of the manipulator is proposed. The amount of end deformation after optimization of the manipulator is analyzed. The maximum deformation is 0.27mm, which meets the requirements. The optimization process provides a reference for the selection of the drive joint parts of the mechanical arm. According to this, the physical design of the mechanical arm is completed and the load test is carried out. The experiment shows that the mechanical arm can still achieve rapid response under the condition of a 2kg end load.

The UAV (unmanned aerial vehicle) unfolding guide rope is the construction process adopted in the tension stringing of overhead power transmission line. At present, due to the limit of UAV control precision, the function of threading the guide rope into the paying-off sheave groove directly cannot be realized, and we can only unfold the guide rope of UAV to the cross arm of iron tower, and then, make the operation personnel at height transfer the guide rope into the steel wire groove of paying-off sheave. Therefore, the construction efficiency of this process is relatively, and there is operation at height, with a certain safety risk. In this project, it is planned to develop a launching device carried by UAV, and this device uses the compressed carbon dioxide (CO2) which is relatively safe as power source, which realizes the instantaneous release of compressed air through electromechanical servo control, and then generate the power which promotes the “rope missle” to fly. The tail of “rope missle” is connected with guide rope, and when it flies forward, the traction guide rope will move forward synchronously. After the “rope missle” threads into the sheave, the compressed air will be released completely, and then, the “rope missle” will transfer into the motion of a free falling body, thus further driving the falling of guide rope, so as to realize the function of “rope missle” tracts the guide rope to realize threading into the paying-off sheave.

The increasing construction of power transmission line promotes the development of construction technology of overhead power transmission line in our country into a brand-new era; while the paving of leading string of traditional overhead power transmission line is still to be completed by climbing the iron tower and manual operation of construction personnel. Therefore, it has been extremely urgent to implement research on the construction process of the power transmission line’s leading string threading into pulley, thus reducing the frequency of operation at height of construction personnel. This paper aims to introduce the ejection construction technology of UAV based on trajectory theory to reconstruct the line tackle device, states the construction process flow of multi-rotor UAV utilizing ejection technology to conduct continuous unreeling and setting of leading string with ejection technology in detail, summarizes the full process of construction, conducts contrastive analysis with traditional construction process, and summarizes the social benefit and economic benefit of new type of construction process.