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In this study, the mechanical model of the electronically controlled knee prosthesis is developed, forward and inverse kinematic analyses are performed, and trajectory tracking for joint space is obtained, respectively. The analyses were carried out considering a cycle of gait walking at a constant speed. Thus, position, velocity and acceleration data of the prosthesis of joint space required for...
This paper presents the biological control for a radially free distributed hexapod robot. The CPG(central pattern generators) network consists of six CPG units based on Hopf neural oscillator that used to generate rhythmic oscillatory signals for the end trajectories of legs. The ring-type network topology of CPG network that consists of six CPG units is established. By computing the inverse kinematics,...
The paper treats a class of human walking robots, the athlete robot (AR). The dynamic equations of this model are generated by Euler Lagrange method as a multi-input-multi-output under-actuated model. The balancing control on one leg in the stance phase is studied. The hierarchical sliding mode control algorithm is proposed. Numerical simulations show the method efficiency.
This paper analyzes the control of a mobile robotic system that utilizes a serpentine robotic tail to assist in the maneuvering and stabilization of quadrupedal locomotion. The goal of this research is to reduce the design and control complexity required in the robot's legs by providing a separate mechanism to help the mobile robot steer and recover from disturbances. The design and dynamic models...
In this paper, we introduce a new scanning technique for detecting landmines and unexploded ordnance (UXO). The manipulator arm carried by a hexapod robot is capable of scanning rough terrain using a typical mine detector. To speed up the landmine detection and marking, both scanning and moving forward will be done simultaneously. The controller will perform two tasks. The first task is to keep the...
In this paper, we present a control method for bipedal robotic walking based on insights we obtain from simple models. Inspired by the virtual pendulum (VP) concept and the spring-mass walking models, we propose a force direction control method to redirect the axial force of a compliant leg in order for walking with upright trunk. We first consider a dynamic simulation of a simple planar walking model...
The goal of this paper is to present a method for generating a basic trajectory for a planar bipedal robot with point feet. Since the mechanism is underactuated, partial feedback linearisation is used as a control method. In order to omit dynamic singularities only relative angles are used in the output function and the information about the absolute position of the robot is supplied using a virtual...
The lift-and-carry of non-rigid objects is challenging for both people and bipedal robots. Examples include lifting and carrying jugs, jerry cans or bags that are respectively filled with water, gasoline or sand. Carrying such objects often makes it difficult to walk due to the shifting center-of-mass. As such, tripping and falling are risks. Such lift-and-carry is a common material handling task...
In this paper, previous works on the Model Predictive Control (MPC) and the Divergent Component of Motion (DCM) for bipedal walking control are extended. To this end, we employ a single MPC which uses a combination of Center of Pressure (CoP) manipulation, step adjustment, and Centroidal Moment Pivot (CMP) modulation to design a robust walking controller. Furthermore, we exploit the concept of time-varying...
This paper proposes an approximate-kinetic-model-based self-adaptive (AKS) control system to rapidly generate target walking speed by an underactuated compasslike bipedal walker. First, a model of the underactuated compass-like bipedal walker is built, and an open-loop system is introduced and analysed as the prototype of AKS system. Second, the control law of AKS is described in detail. The dynamic...
When limbs are decoupled, we find that trajectory outcomes in mechanical systems subject to unilateral constraints vary differentiably with respect to initial conditions, even as the contact mode sequence varies.
We present an algorithm that generates walking motions for quadruped robots without the use of an explicit footstep planner by simultaneously optimizing over both the Center of Mass (CoM) trajectory and the footholds. Feasibility is achieved by imposing stability constraints on the CoM related to the Zero Moment Point and explicitly enforcing kinematic constraints between the footholds and the CoM...
This paper presents, compares, and experimentally implements two robust model-based controllers for transfemoral prosthetic walking: the robust passivity (RP) controller and the robust sliding mode (RS) controller. These findings constitute the first steps toward using model-based controllers for prosthetic devices as an alternative to commonly-used variable impedance and proportional-derivative (PD)...
The Underactuated Lightweight Tensegrity Robotic Assistive Spine (ULTRA Spine) project is an ongoing effort to develop a flexible, actuated backbone for quadruped robots. In this work, model-predictive control is used to track a trajectory in the robot's state space, in simulation. This is the first work that tracks an arbitrary trajectory, in closed-loop, in the state space of a spine-like tensegrity...
Bipedal humanoid robots have complex dynamics and they are intrinsically unstable. Although, bipedal robots have a similar kinematic architecture to a human and they are the most appropriate type of robots to operate in human environments, developing a humanoid robot that has robust is a difficult task. This paper proposes an omnidirectional walking engine that takes into account the push recovery...
The aim of this paper is to develop a robust control algorithm for a five-link biped robot with one degree of underactuation to climb stairs in a natural manner. The biped consists of a five-link planar robot with two actuators at the hip and another two at the knee joints. A robust sliding mode controller is proposed to track gait trajectories while climbing stairs. The control signals are computed...
This paper introduces a novel control system of bipedal robots on uneven terrain. Since this method does not require to measure Zero Moment Point (ZMP), the tracking performance of the controller is not deteriorated by the noise on a measured ZMP. Moreover, the robot withstands frequent perturbations because of its two-degree-of-freedom structure. The robot is stabilized by Center of Mass (COM) regulation...
In this paper, an enhanced linear inverted pendulum model (LIPM) and a gait planning algorithm are proposed. The LIPM is a widely used concept for gait reference generation, and it provides a simplified model for planning a center of mass trajectory when given a proper zero moment point trajectory. However, one of the assumptions of LIPM is that the legs of the robot are massless, so that the mass...
In this paper, we show an underactuated bipedal walker can travel on steep slope by bending its stance knee when the swing foot hits on the ground. First, we introduce an underactuated bipedal model with knees which can be controlled knee angles by applying the control input. Second, we consider an input-output linearization formula with three desired time trajectory functions and output-following...
DARwIn-OP is an anthropomorphic robot with intelligence-open platform and twenty degree of freedom(DOF), in which joints are driven by dynamixel motor MX-28T. This paper mainly investigates kinematics analysis and gait planning issues of DARwIn-OP. Denavit-Hartenberg method is applied to direct kinematics and inverse kinematics analysis. In trajectory generation, based on foothold point locations,...
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