scholarly journals Fundamental Limits in Combine Harvester Header Height Control

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Yangmin Xie ◽  
Andrew G. Alleyne ◽  
Ashley Greer ◽  
Dustin Deneault
Keyword(s):  
Closed Loop ◽  
Open Loop ◽  
The Other ◽  
Specific System ◽  
Fundamental Limits ◽  
Height Control ◽  
Sensor Actuator ◽  
Loop Transfer Function ◽  
Loop Bandwidth ◽  
Combine Harvester

This paper investigates fundamental performance limitations in the control of a combine harvester's header height control system. There are two primary subsystem characteristics that influence the achievable bandwidth by affecting the open loop transfer function. The first subsystem is the mechanical configuration of the combine and header while the second subsystem is the electrohydraulic actuation for the header. The mechanical combine + header subsystem results in an input–output representation that is underactuated and has a noncollocated sensor/actuator pair. The electrohydraulic subsystem introduces a significant time delay. In combination, they each reinforce the effect of the other thereby exacerbating the overall system limitation of the closed loop bandwidth. Experimental results are provided to validate the model and existence of the closed loop bandwidth limitations that stem from specific system design configurations.

Integrated Plant and Controller Design of a Combine Harvester System

2011 ◽  
Author(s):  
Yangmin Xie ◽  
Andrew Alleyne
Keyword(s):  
Controller Design ◽  
Design Method ◽  
Open Loop ◽  
System Response ◽  
Height Control ◽  
Loop Bandwidth ◽  
Original Plant ◽  
Bandwidth Limitation ◽  
Combine Harvester ◽  
And Control

This article proposes a plant and controller design method based on performance analysis of a header height control problem on a combine harvester. The achievable bandwidth was found to be limited by the under-actuated and non-collocated features of the mechanical structure, and a parameter optimization is then applied to solve this problem by improving the property of open loop zeros and poles. H∞ controller design is used to achieve the best performance with the considerations of tracking bandwidth, disturbance rejection and control energy. The simulation results show that this approach can obtain relatively high closed loop bandwidth which surpasses the bandwidth limitation of the original plant. The simulation of tracking comparison also shows that the integrated plant and controller design generate a superior system response.

Modeling of a Hydraulic Elevator Driven by an Open-Loop Control

2009 ◽  
Author(s):  
Roberto Strada ◽  
Alberto Oldani
Keyword(s):  
Power Generation ◽  
Closed Loop ◽  
Open Loop ◽  
The Other ◽  
Open Loop Control ◽  
Proportional Valve ◽  
Loop Control ◽  
Complete Knowledge ◽  
Motion Time ◽  
Loop Control System

Electro-hydraulic elevators are widely used systems, especially in low level buildings, due to their very good ratio between power generation and dynamic response. Generally, the goal of an elevator system is just to reach the floor with a precision enough to be comfortable for the passengers, without the need to follow a specific law of motion; hence an open-loop control system could be enough. Otherwise such a kind of solution reduces the number of components, bringing down the costs of production. On the other hand a complete knowledge of the mechanical system’s behaviour is required. In this work we deal with the analysis of the behaviour of a commercial hydraulic elevator driven by an open loop control that monitors the downstream pressure of the proportional valve supplying the cylinder. At the end of the paper, a closed loop solution based on the pressure measurement and on the motion time is proposed.

Study of Dominant Performance Characteristics in Robot Transmissions

1993 ◽  
Vol 115 (3) ◽  
pp. 472-482 ◽  
Author(s):  
H. Schempf ◽  
D. R. Yoerger
Keyword(s):  
Force Control ◽  
Closed Loop ◽  
Stability Margin ◽  
Viscous Friction ◽  
Open Loop ◽  
Phase Lag ◽  
Stability Margins ◽  
Loop Bandwidth ◽  
Hard Contact ◽  
Following Error

Six different transmission types suitable for robotic manipulators were compared in an experimental and theoretical study. Single-degree-of-freedom mechanisms based on the different transmissions were evaluated in terms of force control performance, achievable bandwidth, and stability properties in hard contact tasks. Transmission types considered were (1) cable reducer, (2) harmonic drive, (3) cycloidal disk reducer, (4) cycloidal cam reducer, (5) ball reducer, and (6) planetary/cycloidal gear head. Open loop torque following error, attenuation and phase lag, and closed loop bandwidth and stability margin were found to be severely dominated by levels of inertia, stiffness distribution and variability, stiction, coulomb and viscous friction, and ripple torque. These aspects were quantified and shown to vary widely among all transmissions tested. The degree of nonlinearity inherent in each transmission affected its open and closed loop behavior directly, and limited the effectiveness of controller compensation schemes. Simple transmission models based on carefully measured transmission characteristics are shown to predict stability margins and achievable force-control bandwidths in hard contact to within a 5 to 15 percent error margin.

Design of a High-Bandwidth XY Nanopositioning Stage for High-Throughput Micro/Nano Manufacturing

2010 ◽  
Author(s):  
Sebastian Polit ◽  
Jingyan Dong
Keyword(s):  
Mechanism Design ◽  
High Throughput ◽  
Closed Loop ◽  
Open Loop ◽  
Dynamic Responses ◽  
Element Analysis ◽  
Loop Bandwidth ◽  
Decoupled Motion ◽  
High Bandwidth ◽  
Critical Requirement

A high natural frequency (open-loop bandwidth) is a critical requirement for nanopositioners in high-throughput nanomanufacturing and nano-metrology applications. This paper presents the design and analysis of a high-bandwidth nanopositioning XY stage. The monolithic stage design has two axes and each axis is comprised of a doubly-clamped beam and a parallelogram hybrid flexure with complaint beams and circular flexure hinges. The doubly-clamped beam that is actuated by a piezoelectric actuator acts as a linear prismatic axis. The parallelogram hybrid flexures are used to decouple the actuation effect from the other axis. The mechanism design decouples the motion in the X and Y directions and restricts parasitic rotations in the XY plane while allowing for an increased bandwidth with linear kinematics in the operating region (or workspace). Kinematic and dynamic analysis shows that the mechanical structure of the stage has decoupled motion in XY direction, while achieving high bandwidth and good linearity. Finite element analysis is adapted to verify the dynamic responses from theoretical analysis. The stage is actuated by piezoelectric stack actuators, and two capacitive gauges were added to the system to build a closed-loop positioning system. The results from frequency test show that the resonation frequencies of the two vibrational modes are over 8K Hz. The stage is capable of about 15 microns of motion along each axis with a resolution of about 1 nanometer. Due to parallel kinematic mechanism design, a uniform performance is achieved across the workspace. A PI controller is implemented for the stage and a high closed-loop bandwidth is obtained.

A Digital Compensator Design for Electrohydraulic Single-Rod Cylinder Position Control Systems

1990 ◽  
Vol 112 (3) ◽  
pp. 403-409 ◽  
Author(s):  
J. Watton
Keyword(s):  
Control Systems ◽  
Closed Loop ◽  
Position Control ◽  
Open Loop ◽  
Closed Loop System ◽  
Forward Algorithm ◽  
Loop Transfer Function ◽  
Compensator Design ◽  
Feedback Algorithm ◽  
Position Control System

A digital compensator using a forward algorithm, F(z−1), and a feedback algorithm, H(z−1), is developed for an electrohydraulic position control system incorporating an underlapped servovalve and a single-rod cylinder. The main problems encountered with designing such a closed-loop system are discussed, and it is shown how the filter coefficients may be easily determined for a particular class of open-loop transfer function. An excellent comparison between theory and experiment is obtained and it is deduced that one coefficient only need be changed in the forward algorithm for such gain-change dominant systems.

scholarly journals On PID Controller Design by Combining Pole Placement Technique with Symmetrical Optimum Criterion

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Viorel Nicolau
Keyword(s):  
Transfer Function ◽  
Closed Loop ◽  
Controller Design ◽  
Open Loop ◽  
Pole Placement ◽  
Loop Transfer Function ◽  
Heading Control ◽  
Pid Controller Design ◽  
Analytical Expressions ◽  
Placement Technique

In this paper, aspects of analytical design of PID controllers are studied, by combining pole placement technique with symmetrical optimum criterion. The proposed method is based on low-order plant model with pure integrator, and it can be used for both fast and slow processes. Starting from the desired closed-loop transfer function, which contains a second-order oscillating system and a lead-lag compensator, it is shown that the zero value depends on the real-pole value of closed-loop transfer function. In addition, there is only one pole value, which satisfies the assumptions of symmetrical optimum criterion imposed to open-loop transfer function. In these conditions, by combining the pole placement technique with symmetrical optimum criterion, the analytical expressions of the controller parameters can be simplified. For simulations, PID autopilot design for heading control problem of a conventional ship is considered.

scholarly journals Prediction error's minimization through a controller based on a Metaheuristic Algorithm

2020 ◽  
Vol 43 (3) ◽  
pp. 5-11
Author(s):  
Viorel Mînzu
Keyword(s):  
Optimal Control ◽  
Theoretical Analysis ◽  
Optimal Control Problem ◽  
Control Problem ◽  
Predictive Control ◽  
Closed Loop ◽  
Open Loop ◽  
The Other ◽  
Metaheuristic Algorithm ◽  
Prediction Technique

A Metaheuristic Algorithm (MA) can be a realistic method to solve a given Optimal Control Problem (OCP), but the result is an open-loop solution. If the Metaheuristic Algorithm is integrated within the Model Predictive Control (MPC) structure, a closed-loop solution can be achieved. The controller works using a prediction technique and prediction error's minimization. On the other side, the MA optimizes (minimizes or maximizes) the OCP's objective function. The controller is faced with two optimization tasks. This paper proves through theoretical analysis and simulations that the prediction error's minimization is implicitly accomplished.

STABILITY OF CLOSED LOOP FRACTIONAL ORDER SYSTEMS AND DEFINITION OF DAMPING CONTOURS FOR THE DESIGN OF CONTROLLERS

2012 ◽  
Vol 22 (04) ◽  
pp. 1230013 ◽  
Author(s):  
PATRICK LANUSSE ◽  
ALAIN OUSTALOUP ◽  
VALERIE POMMIER-BUDINGER
Keyword(s):  
Transfer Function ◽  
Fractional Order ◽  
Half Plane ◽  
Closed Loop ◽  
Open Loop ◽  
Damping Factor ◽  
Closed Loop Systems ◽  
Phase Slope ◽  
Loop Transfer Function ◽  
The Right

Fractional complex order integrator has been used since 1991 for the design of robust control-systems. In the CRONE control methodology, it permits the parameterization of open loop transfer function which is optimized in a robustness context. Sets of fractional order integrators that lead to a given damping factor have also been used to build iso-damping contours on the Nichols plane. These iso-damping contours can also be used to optimize the third CRONE generation open loop transfer function. However, these contours have been built using nonband-limited integrators, even if such integrators reveal to lead to unstable closed loop systems. One objective of this paper is to show how the band-limitation modifies the left half-plane dominant poles of the closed loop system and removes the right half-plane ones. Also presented are how to obtain a fractional order open loop transfer function with a high phase slope and a useful frequency response, and how the damping contours can be used to design robust controllers, not only CRONE controllers but also PD and QFT controllers.

Ventilatory stability to transient CO2 disturbances in hyperoxia and normoxia in awake humans

1997 ◽  
Vol 83 (2) ◽  
pp. 466-476 ◽  
Author(s):  
Jie Lai ◽  
Eugene N. Bruce
Keyword(s):  
Closed Loop ◽  
Transfer Functions ◽  
Response Duration ◽  
Periodic Breathing ◽  
Open Loop ◽  
Phase Delay ◽  
Ventilatory Responses ◽  
Loop Transfer Function ◽  
Random Disturbances ◽  
Peak Value

Lai, Jie, and Eugene N. Bruce. Ventilatory stability to transient CO2 disturbances in hyperoxia and normoxia in awake humans. J. Appl. Physiol. 83(2): 466–476, 1997.—Modarreszadeh and Bruce ( J. Appl. Physiol. 76: 2765–2775, 1994) proposed that continuous random disturbances in arterial [Formula: see text] are more likely to elicit ventilatory oscillation patterns that mimic periodic breathing in normoxia than in hyperoxia. To test this hypothesis experimentally, in nine awake humans we applied pseudorandom binary inspired CO2 fraction stimulation in normoxia and hyperoxia to derive the closed-loop and open-loop ventilatory responses to a brief CO2 disturbance in terms of impulse responses and transfer functions. The closed-loop impulse response has a significantly higher peak value [0.143 ± 0.071 vs. 0.079 ± 0.034 (SD) l ⋅ min−1 ⋅ 0.01 l CO2 −1, P = 0.014] and a significantly shorter 50% response duration (42.7 ± 13.3 vs. 72.3 ± 27.6 s, P = 0.020) in normoxia than in hyperoxia. Therefore, the ventilatory responses to transient CO2 disturbances are less damped (but generally not oscillatory) in normoxia than in hyperoxia. For the closed-loop transfer function, the gain in normoxia increased significantly ( P < 0.0005), while phase delay decreased significantly ( P< 0.0005). The gain increased by 108.5, 186.0, and 240.6%, while phase delay decreased by 26.0, 18.1, and 17.3%, at 0.01, 0.03, and 0.05 Hz, respectively. Changes in the same direction were found for the open-loop system. Generally, an oscillatory ventilatory response to a small transient CO2 disturbance is unlikely during wakefulness. However, changes in parameters that lead to additional increases in chemoreflex loop gain are more likely to initiate oscillations in normoxia than in hyperoxia.

scholarly journals CONTROL OF BODY HEIGHT IN A STICK INSECT WALKING ON A TREADWHEEL

1993 ◽  
Vol 181 (1) ◽  
pp. 141-155 ◽  
Author(s):  
H. Cruse ◽  
J. Schmitz ◽  
U. Braun ◽  
A. Schweins
Keyword(s):  
Control System ◽  
Linear Relationship ◽  
Closed Loop ◽  
Dynamic Behaviour ◽  
Dynamic Properties ◽  
Body Height ◽  
Stick Insect ◽  
Open Loop ◽  
Carausius Morosus ◽  
Height Control

The properties of the system that controls the distance between body and ground was investigated in the stick insect Carausius morosus. The insect walked on a lightweight double treadwheel under open-loop or closed-loop conditions. The open-loop investigations show that the dynamic behaviour of the height-control system in the walking animal can be described in terms of a simple proportional system with negligible dynamic properties, and it is therefore much simpler than the height-control system in the standing animal. Under open-loop conditions, we found no coupling between contralateral or ipsilateral legs. This agrees with the findings on standing animals. The force- height characteristic shows two ranges, in each of which the system exhibits a linear relationship but a different slope. Under closed-loop conditions, the force-height characteristic shows the same two linear ranges, but the slopes are greater than under open-loop conditions. Because the height controller of each leg can be considered to act like a spring, this result means that under closed-loop conditions the controller is stiffer than it is under open-loop conditions.

Sign in / Sign up

Export Citation Format

Share Document