The complexity and nonlinear characteristics of the individual frequency-active power control strategy; the diversity and time-varying nature of control parameters of each photovoltaic power station in the grid-connected photovoltaic cluster will make it difficult to estimate the equivalent inertia of the full power system under high-penetration rate photovoltaic grid-connected operation. At present, the dispatch center of utility is disabled to directly obtain the current system equivalent inertia level under the known photovoltaic penetration rate and the grid-connected control strategy with parameters of each photovoltaic power station in the cluster. Therefore, this paper establishes the static function between system equivalent inertia and photovoltaic penetration rate with its corresponding control parameters based on inertia identification. This function can help the dispatch center directly calculate the current equivalent inertia of the system, which can then be used to assist in accurately arranging the power generation plan of each photovoltaic power station in the cluster in the future.

A humanoid neck design with low motion noise yields a cable-driven parallel manipulator to imitate two axis rotational motion of a human neck. The fixed base and moving platform of the manipulator are connected by four cables and a column compression spring. The four cables are actuated separately, while the spring can support weight on the moving platform. Although similar manipulators exist in literature, the analysis for them is scarce. The difficulty is that while traditional parallel manipulator usually has a rigid kinematic chain as the spine, this manipulator has a flexible spring. With the spring's lateral bending motion, new approach must be adopted to solve the kinematics. In this paper, we propose a method which combines the kinematics with the statics to solve them simultaneously. We parameterize the posture of the moving platform with four parameters and consider one of them as parasitic motion. Using the spring bending equation, we can obtain the parasitic motion and solve the inverse position problem. The analysis in this paper provides a novel way to analyze parallel manipulator with a spring spine, and it can be applied to other manipulators with flexible spines.

A miniature robot with continuous jumping ability is presented in this paper. The robot has a dimension about 6cm×8cm×2cm and weighs 20 grams. To achieve continuous jumping, various mechanisms are needed including the jumping mechanism, energy store and release mechanism, self-righting mechanism, and jumping direction changing mechanism. The design and analysis for those mechanisms are elaborated in this paper. Moreover, implementation and experimental results are also presented. It is shown that the robot can jump higher than 55cm with a 75° takeoff angle. The robot can be used as mobile sensors and deployed in the areas of rugged terrain and natural obstacles which are not suitable for sensors with wheels.

This paper presents our recently developed humanoid neck system that can effectively mimic motion of human neck with very low motion noises. The feature of low motion noises allows our system to work like a real human head/neck. Thus the level of acoustic noises from wearable equipments, such as donning respirators or chemical-resistant jackets, induced by human head motion can be simulated and investigated using such a system. The objective of this investigation is to facilitate using head-worn communication devices for the person who wears the protective equipment/uniform that usually produces communication-noise when the head/neck moves. Our low motion-noise humanoid neck system is based on the spring structure, which can generate 1 Degree of Freedom (DOF) jaw movement and 3DOF neck movement. To guarantee the low-noise feature, no noise-makers like gear and electro-driven parts are embedded in the head/neck structure. Instead, the motions are driven by seven cables, and the actuators pulling the cables are sealed in a sound insulation box. Furthermore, statics analysis of the system has been processed completely. Experimental results validate the analysis, and clearly show that the head/neck system can greatly mimic the motions of human head with an A-weighted noise level of 30 dB or below.

Mobile sensors with jumping ability provide several advantages compared with the traditional wheeled sensors such as ability to move in rugged terrain. A controllable jumping robot for this purpose is described in this paper. The robot has dimension about 9.5cm × 9cm × 3cm and weighs 54.1 grams. It can perform the jumping process continuously. This paper focuses on the mechanisms to achieve such a continuous jumping ability, including the jumping mechanism, energy store and release mechanism, and self-righting mechanism. Detail implementation and experimental results are also given in this paper. It is shown that with a 75° takeoff angle, the robot can jump about 20cm in height.

The translational oscillation with a rotational actuator (TORA) system has been used as a benchmark for motivating the study of nonlinear control techniques. In this paper, modeling and control of a novel 2-dimensional TORA (2DTORA) are presented. The 2DTORA is an underactuated mechanical system which has one actuated rotor and two unactuated translational carts. The dynamics of the 2DTORA system is derived based on Lagrange equations. The total energy of the system is employed to show the passivity property of 2DTORA, and then a simple state feedback control algorithm is developed based on a proper Lyapunov function including energy item. Finally, simulation results are demonstrated.

This paper describes our updated system for industrial robot joint offset calibration. The system consists of an IRB1600 industrial robot, a laser tool attached to the robot's end-effector, a portable position-sensitive device (PPD), and a PC based controller. By aiming the laser spot to the center of position-sensitive-detector (PSD) on the PPD with different robot configurations, the developed system ideally implements our proposed calibration method called the virtual line-based single-point constraint approach. However, unlike our previous approach, the calibration method is extended to identify the offset parameters with an uncalibrated laser tool. The position errors of the PPD and the sensitivities of error in the PSD plane to the variation of joint angles are analyzed. Two different robot configuration patterns are compared by implementing the calibration method. Both simulation and real experimental results are consistent with the mathematical analysis. Experimental results with small (10−3−10−2) mean and standard deviation of parameters error verify the effectiveness of both the sensitivity analysis and the developed system.

Nanomanipulation with Atomic force microscopy (AFM) is one of the fundamental tools for nano-manufacturing. The control of the nanomanipulation system requires accurate feedback from the piezoelectric actuator and high frequency response of the control system. We designed and implemented two distinct control schemes by using real-time Linux. The aim is to study various factors in the control of the AFM based nanomanipulation system. By integrating the original controller with the external Linux real-time controller, we achieved a stable system with high response frequency. Finally this multiple input single output (MISO) system is validated to be an effective and efficient tool for the controlling of the nanolithography operation through a haptic device.

This paper discusses the dynamical servo control problem for the Acrobot - a mechanics with two links while just one actuator applied to the second link. The dynamical servo control aims to access generic points in the state space not just the equilibrium points. Stabilizing of generic points is impossible and a possible way is to stabilize some periodic orbits passing through the desired points. Virtual constraints are used to generate such orbits. By analyzing the integration of the zero dynamics of the Acrobot subjected to virtual constraints, conditions of whether there is an orbit passing through the desired point and the orbit function are found. A cascade control strategy is proposed to stabilize both the virtual constraint and the orbit function which decides the system behavior. Simulation results show the effectiveness of the control law.

We present the design and implementation of a new jumping robot for mobile sensor network. Unlike other jumping robots, the robot is based on a simple two-mass-spring model. After we throw it on ground, it can stabilize itself and then jump once. The detailed mechanism design including the load holding and self-stabilization are presented. Jumping heights and distances with different robot weights are measured and compared with calculated values from the two-mass-spring model.