An Efficient Gait-generating Method for Electrical Quadruped Robot Based on Humanoid Power Planning Approach

The research field of legged robots has always relied on the bionic robotic research,especially in locomotion regulating approaches,such as foot trajectory planning,body stability regulating and energy efficiency prompting.Minimizing energy consumption and keeping the stability of body are considered as two main characteristics of human walking.This work devotes to develop an energy-efficient gait control method for electrical quadruped robots with the inspiration of human walking pattern.Based on the mechanical power distribution trend,an efficient humanoid power redistribution approach is established for the electrical quadruped robot.Through studying the walking behavior acted by mankind,such as the foot trajectory and change of mechanical power,we believe that the proposed controller which includes the bionic foot movement trajectory and humanoid power redistribution method can be implemented on the electrical quadruped robot prototype.The stability and energy efficiency of the proposed controller are tested by the simulation and the single-leg prototype experi-ment.The results verify that the humanoid power planning approach can improve the energy efficiency of the electrical quadruped robots.     

Turning in a Bipedal Robot

We report the development of turning behavior on a child-size bipedal robot that addresses two common scenarios: turning in place and simultaneous walking and turning. About turning in place, three strategies are investigated and compared, including body-first, leg-first, and body/leg-simultaneous. These three strategies are used for three actions, respectively: when walking follows turning immediately, when space behind the robot is very tight, and when a large turning angle is desired. Concerning simultaneous walking and turning, the linear inverted pendulum is used as the motion model in the single-leg support phase, and the polynomial-based trajectory is used as the motion model in the double-leg support phase and for smooth motion connectivity to motions in a priori and a posteriori single-leg support phases. Compared to the trajectory generation of ordinary walking, that of simultaneous walking and turning introduces only two extra parameters: one for determining new heading direction and the other for smoothing the Center of Mass (COM) trajectory. The trajectory design methodology is validated in both simulation and experimental environments, and successful robot behavior confirms the effectiveness of the strategy.     

Geometric design of crab-like climbing and walking robots

1 Introduction Many CLAWAR (CLimbing And WAlking Robots)researchers have concentrated on navigation, gait gen-eration and control, rather than mechanical design. Whenprototypes have been developed, it has often been as-sumed that the mechanical design principles are knownand the problem is one of applying them. In practise, thisis far from the truth, as the performance of existing pro-totypes testifies. The most common design approach is tocopy the geometry of insects and mammals wit…     

Optimization of fed-batch fermentors by iterative dynamic programming

By using penalty functions to handle state constraints, iterative dynamic programming can be used in a straightforward manner for the optimization of fedbatch fermentors. No computational difficulties were encountered and better results are obtained than previously reported in the literature for a fed-batch fermentor for biosynthesis of penicillin. (c) 1993 Johy Wiley & Sons, Inc.     

A Bio-Inspired Biped Water Running Robot Incorporating the Watt-I Planar Linkage Mechanism

In this paper, a biped water running robot is developed by mimicking the water-running pattern of basilisk lizards. The dynamic mechanism of the robot was studied based on Watt-I planar linkages, and the movement trajectory of the double bar Assur Group was deduced to simulate the water-running foot trajectories of the basilisk lizard. A Central Pattern Generator （CPG）-based fuzzy control method was proposed to control the robot for realizing balance control and gait adjustment. The effectiveness of the proposed control method was verified on the prototype of a water running robot （weight： 320 g）. When the biped robot is running on water, the average force generated by the propulsion mechanism is 1.3 N, and the robot body tilt angle is 5~. The experiment results show that the propulsion mechanism is effective in realizing the basilisk lizards-like water running patterns, and the CPG-based fuzzy control method is effective in keeping the balance of the robot.     

Why fly the extra mile? Latitudinal trend in migratory fuel deposition rate as driver of trans‐equatorial long‐distance migration

Trans‐equatorial long‐distance migrations of high‐latitude breeding animals have been attributed to narrow ecological niche widths. We suggest an alternative hypothesis postulating that trans‐equatorial migrations result from a possible increase in the rate at which body stores to fuel migration are deposited with absolute latitude; that is, longer, migrations away from the breeding grounds surpassing the equator may actually enhance fueling rates on the nonbreeding grounds and therewith the chance of a successful, speedy and timely migration back to the breeding grounds. To this end, we first sought to confirm the existence of a latitudinal trend in fuel deposition rate in a global data set of free‐living migratory shorebirds and investigated the potential factors causing this trend. We next tested two predictions on how this trend is expected to impact the migratory itineraries on northward migration under the time‐minimization hypothesis, using 56 tracks of high‐latitude breeding shorebirds migrating along the East Asian‐Australasian Flyway. We found a strong positive effect of latitude on fuel deposition rate, which most likely relates to latitudinal variations in primary productivity and available daily foraging time. We next confirmed the resulting predictions that (1) when flying from a stopover site toward the equator, migrants use long jumps that will take them to an equivalent or higher latitude at the opposite hemisphere; and (2) that from here onward, migrants will use small steps, basically fueling only enough to make it to the next suitable staging site. These findings may explain why migrants migrate “the extra mile” across the equator during the nonbreeding season in search of better fueling conditions, ultimately providing secure and fast return migrations to the breeding grounds in the opposite hemisphere.     

Optimal production of curdlan by Agrobacterium sp. with feedback inferential control of optimal pH profile

The pH control was important for curdlan production with Agrobacterium sp. ATCC31750. Specific cell growth rate was the highest at pH 7 and the specific curdlan production rate was at pH 5.5. The pH profiles maximizing curdlan production was changed from pH 7 optimal for cell growth to pH 5.5 optimal for curdlan production after ammonium consumption. The feedback inferential control methods, with easily measurable variables such as NaOH addition for pH control and dissolved oxygen (DO), were also applied. The pH was successfully controlled to follow optimal profiles and the maximal production of curdlan (60 g l^–1 in 120 h) was achieved with feedback optimal control.     

Optimal nonsingular control of fed-batch fermentation

Presented is a new simple method for multidimensional optimization of fed-batch fermentations based on the use of the orthogonal collocation technique. Considered is the problem of determination of optimal programs for fermentor temperature, substrate concentration in feed, feeding profile, and process duration. By reformulation of the state and control variables is obtained a nonsingular form of the optimization problem which has considerable advantage over the singular case since a complicated procedure for determination of switching times for feeding is avoided. The approximation of the state variables by Lagrange polynomials enables simple incorporation of split boundary conditions in the approximation, and the use of orthogonal collocations provides stability for integration of state and costate variables. The interpolation points are selected to obtain highest accuracy for approximation of the objective functional by the Radau-Lobatto formula. The control variables are determined by optimization of the Hamiltonian at the collocation points with the DFP method. Constraints are imposed on state and control variables.The method is applied for a homogeneous model of fermentation with volume, substrate, biomass, and product concentrations as the state variables. Computer study shows considerable simplicity of the method, its high accuracy for low order of approximation, and efficient convergence.     

The feasible modes of optimal operation of bioreactor with inlet and outlet feed streams

The fermentation system with inlet and outlet feed rates were classified into nine possible operations and the feasible modes of optimal operation were checked. The feasible modes of optimal operation were determined directly from theoretical evaluation with the nonsingular transformation approach. The batch or fedbatch operations were feasible modes of optimal operation and the CSTR was analyzed with steady state analysis separately from that of dynamic operation. It was possible to determine the feasible modes of optimal operation with nonsingular transformation without checking all the cases of possible operation.     

具有天敌捕食的鼠害综合防治模型研究

鼠害综合防治是以生态学为基础综合考察各种措施的有机结合与协调 ,综合运用生态学、经济学、环境保护学、系统工程学的观点 ,充分利用自然因素控制鼠害 ,以取得较好的经济效益、生态效益和社会效益。害鼠种群动态、天敌类群动态以及植物群体生长动态是综合防治的基本理论问题 ,确定经济阈值是实现害鼠种群数量科学控制的重要前提[1] 。在综合防治过程中 ,如何最大限度地发挥天敌的作用 ,并将这种作用与其他自然限制因素以及人为防治措施相互协调 ,共同作用 ,是鼠害防治实践中最重要的课题之一 [2 ]。本文先简要综述天敌控制鼠害的研究成果 …     

Optimal control and cost effectiveness analysis for Newcastle disease eco-epidemiological model in Tanzania

In this paper, a deterministic compartmental eco- epidemiological model with optimal control of Newcastle disease (ND) in Tanzania is proposed and analysed. Necessary conditions of optimal control problem were rigorously analysed using Pontryagin's maximum principle and the numerical values of model parameters were estimated using maximum likelihood estimator. Three control strategies were incorporated such as chicken vaccination (preventive), human education campaign and treatment of infected human (curative) and its' impact were graphically observed. The incremental cost effectiveness analysis technique used to determine the most cost effectiveness strategy and we observe that combination of chicken vaccination and human education campaign strategy is the best strategy to implement in limited resources. Therefore, ND can be controlled if the farmers will apply chicken vaccination properly and well in time.