International Journal of Robotics
Volume:6 Issue: 1, Spring 2020

This study introduces a wearable in-shoe system for real-time monitoring and measurement of the plantar pressure distribution of the foot using eleven sensing elements. The sensing elements utilized in ShrewdShoe have been designed in an innovative way, they are based on a barometric pressure sensor covered with a silicon coating. The presented sensing element has great linearity up to 300 N and is very durable. It can withstand excessive burst pressures without any damage. This makes ShrewdShoe applicable in a variety of fields such as gait analysis, activity analysis, sports performance optimization, and detection of gait disorders. ShrewdShoe comes with a built-in IoT (Internet of things) module in order to wirelessly communicate with a PC or smartphone. Due to its low cost and durability, it can be used for everyday wear in order to continuously acquire data. Plantar pressure distribution of the foot maps has been constructed based on obtained data and used for preliminary validation of sensor readings.

Wheeled Mobile Robots (WMRs) are simple, easy to move on hard and level terrain and can be controlled effectively. Due to these merits, many researchers have studied the challenges of WMRs. To improve the payload transportation capability of wheeled vehicles, one or several platform, named as trailer, may towed to a tractor wheeled platform. In the current paper, for the first time, the motion control of such tractor trailer systems is addressed while the actuator dynamics is considered. Toward this goal, the system kinematics and dynamics will be derived and will be coupled to its actuators model. To control the considered nonholonomic system, the technique of input-output feedback linearization along with look-ahead point notion will be utilized. Besides, some of the imprecise parameters in the proposed model-based controller are identified in an on-line manner. The obtained computer simulation results support the soundness of the proposed controller.

Known for their lower costs and numerous applications, cable robots are an attractive research field in robotic community. However, considering the fact that they require an accurate installation procedure and calibration routine, they have not yet found their true place in real-world applications. This paper aims to propose a new controller strategy that requires no meticulous calibration and installation procedures and can handle the uncertainties induced as a result of that. It is well known that kinematic uncertainties can lead to loose cables when one deals with a redundantly actuated robot. The control methodology presented in this paper is a simple yet powerful controller based on wave-based theory that can handle the aforementioned loosened cables. Thus, through applying this novel controller, the applications of cable robots to real-world problems has become more feasible. This paper also investigates the performance of the proposed controller and its effectiveness through some practical experiments. We observed that the‎ proposed controller outperforms conventional cascade topologies in‎ ‎terms of tracking smoothness‎.

In this paper, kinetic and kinematic modeling of a 4 wheel steering vehicle is done and its movement is controlled in an optimal way using Linear Quadratic Regulator (LQR). The results are compared with the same control of two-wheel steering case and the advantages are analyzed. In 4 wheel steering vehicles which are nowadays more applicable the number of controlling actuators are more than the required actuators for controllability of the system. As a result, the possible path through which he vehicle can move to transfer between two boundaries is not unique and this fact provides the possibility of optimization of a desired cost function. In this paper after extracting the model of these vehicles based on Jacobian matrix a compromise between the accuracy and controlling effort is selected as the mentioned objective function and the optimal control and its related optimal path is extracted through which the best accuracy and the least input is required. The correctness of modeling and efficiency of the designed optimal controller is verified by the aid of a series of simulation scenarios and also comparing the results between 4 wheel steering vehicles and 2 wheel steering ones.

This paper aims to develop a boundary control solution for a single-link gantry robot manipulator with one axis of rotation. The control procedure is considered with link’s transverse vibrations while system undergoes rigid body nonlinear large rotation and translation. Initially, based on Hamilton principle, governing equations of hybrid motions as a set of partial differential equations (PDE) and ordinary differential equations (ODE) will be derived. The control objectives which are sought for include: moving the system to a desired position, regulating large angular position and finally suppressing the flexible link transverse vibrations simultaneously. By considering novel Lyapunov functions and avoiding any simplifications, In the presence of external boundary disturbance, proper control feedback signals and boundary disturbance observer are introduced in order to reach mentioned control objectives and compensate external boundary disturbance effect simultaneously. At last uniform ultimate boundedness of the closed loop system is proven in which by choosing proper design parameters, system states and position error converge exponentially to a small neighborhood of zero.  In order to illustrate the performance of the proposed control method, numerical simulation results are provided.

Continuum robotic arms that are inspired from nature, have many advantages compared to traditional robots, which motivate researchers in this field. Dynamic modeling and controlling these robots are challenging subjects due to complicated nonlinearities and considerable uncertainties existing in these structures. In this paper, first a dynamic three-dimensional model of the continuum robotic arm is developed as a black-box model through system identification method. The validity of the obtained model is confirmed by the experimental data. Then, by using the obtained model, a hybrid PID-fuzzy controller, which is considered as a model-free controller and does not require the exact model of the system is employed for controlling the position of the end-effector. Finally, obtained results and the performance of the controller in reaching to different positions of the workspace, either trained or not, is discussed.