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This paper is concerned with the problem of teleoperation systems over networks. As is well known, quantization and time delay are unavoidable in computer network communications. Compared with previous work, we consider both of them when analyzing such systems. The controller used in this paper is proportional-derivative(PD) controller, but the output signals of master and slave systems are quantized...
This paper presents a sufficient stability condition for internet-based tele-operation systems in terms of LMI. The tele-operation scheme is modeled in state-space as a time-delay system in retarded form and a delay-independent stability criterion is extracted. By choosing Lyapunov-Krasovski functional, we show that the internet-based tele-operation system is stable and has good performance under...
This paper presents an adaptive haptic control for a one degree-of-freedom surgical device. The control addresses the problem of hitting a solid object too hard in the presence of time delay. The proposed control runs in the inner-loop, with no time delay, and follows commanded forces from the outer loop. A Lyapunov-stable backstepping-with-tuning-functions design provides a way to ensure smooth forces...
In this paper, the channel characteristic of communication disturbance observer (CDOB) based bilateral teleoperation system is analyzed. It is pointed out that this method is a tradeoff between the 4-channel and the 3-channel algorithm. By the analysis, it is visible that the CDOB based approach expresses a 3-channel dynamic characteristic, because the position channel gains are seriously weakened,...
Medical robot can enhance surgery through improved precision, stability, and dexterity, which has brought great benefits for patients. However, it yields a series of disadvantages to the surgeons, such as the bad eye-hand coordination, the ill-designed workstations etc. All these disadvantages can cause human error during operations, and human error is considered to be the major contributing factor...
This paper presents an architecture extending bottom-up visual attention for dynamic scene analysis. In dynamic scenes, particularly when learning actions from demonstrations, robots have to stably focus on the relevant movement by disregarding surrounding noises, but still maintain sensitivity to a new relevant movement, which might occur in the surroundings. In order to meet the contradictory requirements...
In this paper, we designed a 1DOF power assist system for lifting objects. Human's vertical lifting force, comprises of inertial force and gravitational force, was considered as the desired dynamics of the system. We hypothesized that human's perception of object weight due to inertial force might be different from the perceived weight due to gravitational force for lifting object with the power assist...
An object lifted with a power assist robot is always perceived lighter than its actual weight. But, the human operator cannot differentiate between the power assisted weight and the actual weight and eventually applies load force (vertical lifting force) according to the actual weight of the object. This faulty force programming (excessive load force) gives faulty motions to the power assist robot...
The trajectory is one of major issues for a humanoid robot because not every trajectory can provide a stable robot motion. In this paper, a real human motion is used to generate a robot trajectory. Image processing and transformation are used to extract the trajectory from a human motion to a robot trajectory. The dynamic stability of a robot is considered by using the zero moment point (ZMP) because...
This paper proposes a method of cooperative interaction that a human and distributed robots move cooperatively so as to maintain the swarm situation that robots surround the moving human. This paper is concerned with the control for maintaining the high stability of the swarm, and proposes a control algorithm for the robotic swarm in obstacle or slope space. The proposed algorithm for overcoming above...
Among the methods to grant the stability of a telemanipulation system, the bilateral time domain passivity framework has the appealing characteristic to consider both, force and velocity signals exchanged between master and slave systems, and the power introduced or dissipated by the elements that compose the telemanipulation system. In previous works, it has been shown how the bilateral passivity...
This paper focuses on a new proposal system input of impedance control that relates to force reflection (FR) scheme of teleoperation with time varying in communication lines. To improve the tracking performance and transparency, the control algorithm uses one more communication channel to transfer the FR information from the master side to the slave side. Using variable damping values, the contact...
This paper aims to explore the principles of biomimetic biped walking in the sagittal plane. Firstly, a new walking pattern denoted as two-point-foot walking pattern is proposed according to the structure of the foot of human being. Secondly, the energy cycle of the new walking pattern is investigated. Based on the features of the energy cycle, a multi-scale predict algorithm is developed to estimate...
A theoretical framework for generating navigation behaviour patterns in mixed human-robot groups in complex environments is proposed. This framework represents an essential part in the development of a multiple robot-human system for assisting fire-fighters in search and rescue operations in the GUARDIANS project. In order to produce the desired behaviours an artificial potential field method has...
In this paper, we propose control system which supports unicycle operation for human's skill up. Therefore, the unicycle operation analysis method is proposed first, and it is shown usefulness by experiment. The element used for analysis are rider's CP (Center of Pressure) and MBP (Moment Balancing Point) which negates a saddle rotation moment. Using those elements, we propose evaluation method of...
In multimodal tele-cooperation as considered in this paper two humans in distant locations jointly perform a task requiring multimodal including haptic feedback. One human operator teleoperates a remotely placed humanoid robot which is collocated with the human cooperator. Time delay in the communication channel as destabilizing factor is one of the multiple challenges associated with such a tele-cooperation...
In this paper, we show that a biped robot can walk dynamically using a simple control technique inspired from human locomotion. We introduce four critical angles that affect robot speed and step length. Our control approach consists in tuning the PID parameters of each joint for increasing stability of the walk. This method could be easily implemented in real time because it needs acceptable calculation...
Minakata and Hori (1998) proposed a method for real-time variable speed biped walking. From experimental results using that method, we found that there is a suitable relationship between walking speed and step cycle time. Besides, this relationship (we call this the gait characteristic) is similar to that of human walking. We consider the reason for these characteristics. Walking stability at various...
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