The article is devoted to the approach to the quantitative estimation of changes in the functional state of a person during an airplane flight based on the results of stabilometric and oculographic examinations of airplane passengers carried out before and after the flight. Fourteen volunteers of both sexes participated in the study. They performed 21 pairs of pre-flight and post-flight examinations. For the existing sample of volunteers, parameters were identified that had a consistent trend of change. These parameters include visual tracking quality and stabilometric characteristics. In 70 % probes a decrease in the slow phases of optokinetic nystagmus average speed was noted. In most volunteers, changes in the stabilometric parameters for the optokinetic test and the balance test on an unstable support in the form of foam plate are noticeable. The tracking speeds, the average velocity of the pressure center, and the quality index of the equilibrium function decreased after the flight in more than 70 % of all samples. It was noted that the Hurst index after the flight decreased compared to background sample, during get up on the polyurethane foam plate in the vast majority of volunteers. In test before the flight the change in this parameter was multidirectional. In a stabilometric test with a "stepped deviation", in which a volunteer on command made quick bends at a small angle due to a change in the angle in the ankle joint, 75 % of the subjects after the flights showed a decrease in the average speed.

Обсуждается два алгоритма определения матрицы относительной ориентации инерциального блока и тела системы видеоанализа. Решение этой задачи необходимо для дальнейшей совместной обработки данных этих сенсоров в биомеханических исследованиях. В частности, оно требуется для определения ускорения движущегося объекта в условиях гравитации по показаниям трехкомпонентного акселерометра и системы видеоанализа. В этом случае для вычитания из показаний акселерометра составляющих, порожденных силой тяжести, можно использовать данные о местной вертикали хорошо откалиброванной системы видеоанализа. Оба алгоритма используют измерения, полученные для статических положений, отличающихся ориентацией приборных осей относительно гравитационной вертикали, и одновременно позволяют оценивать систематические ошибки акселерометров. Первый алгоритм предполагает ортогональность приборных осей инерциального блока и не учитывает погрешности в информации о масштабных коэффициентах акселерометров. Алгоритм использует соотношения, линеаризованные в окрестности априорных оценок искомых величин. Второй алгоритм не использует априорную информацию об осях приборного трехгранника. В этом случае проводится повторная калибровка блока акселерометров, и помимо нулей и масштабных коэффициентов определяются углы неортогональности инструментальных осей блока. Непосредственным результатом его работы является матрица, которая позволяет определять проекции кажущегося ускорения на координатные оси, связанные с телом системы видеоанализа. Алгоритмы опробованы на экспериментальных данных. Критерием сравнения являлась разность оценок, полученных по различным выборкам измерений. Обработка результатов пробного эксперимента показала, что для неточных микроэлектромеханических систем второй алгоритм дает более устойчивые результаты.

The problem of synthesizing a control law to stabilize a double inverted pendulum installed on a seesaw is considered. The movement of such kind of pendulums in the vertical plane is studied. The seesaw is a segment of a cylinder whose axis is horizontal. This cylindrical segment may perform oscillations while rolling on the horizontal surface without slipping. The lower (first) link of the pendulum is fastened to the seesaw by a cylindrical joint. The axis of this joint is parallel to the cylinder axis as well as to that of the interlink joint. A control torque, whose absolute value is bounded, is applied to the pendulum at the interlink joint. Thus, the system described above has three degrees of freedom and a single control action. Without control, the open-loop system has an unstable equilibrium position, in which both links of the pendulum are directed vertically upwards, and the seesaw is not tilted. Control stabilizing the desired unstable equilibrium is performed in the feedback form with respect to two "unstable" Jordan variables of the open-loop linearized system so as to make, if possible, the attraction domain of the system maximal. Some properties of the controllability and attraction domains are studied. The results of numerical studies are presented.

The paper discusses the possibility of testing and correcting calibration of a portable acceleration recorder under orbital flight conditions. This recorder in-cludes a 3-axis accelerometer. The most difficult stage of calibration tests is the determination of its scale factors. The main difficulty of calibration is the lack of special equipment on the space station. It is proposed to use a standard mass meter installed on the ISS for testing accelerometers. The algorithms considered in the paper use data of the motion of the mass meter platform and the video camera records processing in addition to the recorder readings. For testing the algorithms under earth conditions, recordings were made that simulate conditions of an orbital flight. The proposed algorithms showed 2 % error in determining the scale factors of the accelerometers.

The approaches to determining the horizontal coordinates of the center of mass (CoM) applicablefor force plate are compared. The force plate for which only vertical forces are the measurements takes into account. The first of these approaches uses the information not only about the initial position and rate of CoM, but also about its terminal state. The second is associated with the use of the assumption about the absence of unstable components in the movement and uses frequency filtering methods. Known algorithms were modified to solve the problem in conditions of sufficiently intense movements by a person. The considered modified algorithms were compared for recordings movement of the subjects who performed a “test with a stepwise visual disturbance” on a force plate. A system of video cameras was simultaneously used to determine the coordinates of a marker fixed approximately at the CoM height. The working capacity of all modified algorithms was demonstrated. It was noted that the error of the estimation method using a double filtration in forward and reverse time was lower than in other procedures.

At present, the theory of wheeled robotic systems is being actively developed. In modeling the motion of wheeled robots, one mostly uses the classical nonholonomic motion model, which does not take into account the slip of deformable wheels. Meanwhile, for robots with deformable wheels, nonholonomic models can be inadequate for the design and analysis of control algorithms. This can be the case for statically unstable balancing robots with coaxial wheels, similar in design with such vehicles as Segway. Thus, modeling the motion of a two-wheeled robot taking into account the possibility of wheels slip and analysis of applicability of simplified models are of interest. Such models can be used to develop new control algorithms in active maneuvering, and for preliminary estimates of robustness of algorithms designed using approximate nonholonomic models. This paper focuses on modeling the motion of balancing robots, on analyzing their steady-state motion, and on possibilities of their stabilization. It is shown that for models with deformable wheels in the steady-state motion the body has a forward pitch. Such a pitch is not found in most nonholonomic models.

Сравниваются подходы к определению горизонтальных координат центра масс, применимые для стабилоанализаторов, измерениями которых являются только вертикальные составляющие усилий. Первый из этих подходов использует информацию не только о начальном положении и скорости центра масс, но и о его финальном состоянии. Второй связан с использованием предположения об отсутствии неустойчивых составляющих в движении и использует методы частотной фильтрации. Известные алгоритмы модифицированы для решения задачи в условиях совершения человеком достаточно интенсивных движений. Рассмотренные модифицированные алгоритмы сравнивались для записей движений обследуемых, выполнявших на стабилоанализаторе пробу со ступенчатым отклонением. Одновременно система видеокамер использовалась для определения координат маркера, закрепленного приближенно на высоте центра масс. Продемонстрирована работоспособность всех модифицированных алгоритмов. Отмечено, что погрешность метода оценивания, использующего двойную фильтрацию в прямом и обратном времени, оказалась меньше, чем у других процедур.

Abstract—Problems of optimal control were analyzed for a human motion model for stabilometric tests where the posture changes under a stepwise input action. The presence of a prominent “swing” and an “overshoot” are characteristic of the center-of-pressure trajectories recorded in the test. A one-dimensional inverted pendulum model was used in the study. The solution of the optimal control for the inverted pendulum motion controlled by coupling torque was put in correspondence with the test results. The problems of optimal speed-of-response control and linear–quadratic regulator were considered. The solution of these optimum problems was compared with the stabilometric test results. A modified algorithm was proposed for stabilometric data processing. This motion was shown to reach a stable motor pattern. The swing and overshoot were found to correspond to the acceleration and deceleration stages, respectively.

Several optimal control problems are considered for a human motion model in the case of stabilometric tests when the posture of a person changes under a step disturbance. Such a situation is observed in the case of a galvanic vestibular stimulation or a vibration stimulation of the proprioceptors of shin muscles. Stabilometric tests with visual step disturbance are widespread in Russia. A characteristic feature of center of pressure (COP) trajectories for these tests is the presence of swings and overshoots. The test results are compared with the solutions of optimal control problems devoted to the repositioning of an inverted pendulum by a coupling torque. A speed-of-response problem and an optimal stabilization problem with a quadratic quality criterion are considered. The solutions to these optimum problems are compared with the results of stabilometric tests, which allows one to state a hypothesis on the sources of the above effects.

A very simple model of the process of maintaining balance by a person standing on a seesaw is considered. The model consists of a planar single-link inverted pendulum, which is connected by means of a cylindrical hinge, i.e., an “ankle joint”, to a support in the form of a segment of cylinder, whose axis is perpendicular to the pendulum. The support can oscillate by rolling on a horizontal surface, and the pendulum can oscillate in a plane that is perpendicular to the cylinder axis. The control is a torque applied on the axis of the hinge. This torque is assumed to have a restricted absolute value. A control law is constructed in the form of feedback along a single “unstable” coordinate of the open system in such a manner that the region of attraction of the linearized system would be the maximum possible. Several characteristic trajectories of the system for the control constructed are considered.

He problem of stabilometric test modeling with visual step disturbance is considered. The test consists in the following. The person stands on a force plate, look at the screen on which the target and center movement of the pressure person are displayed. COP position is given by force plate indications. At the test beginning the center of a target corresponds to average COP position on the basic plane. During test target position make change and the person is asked to change quickly body position due to change of an ankle angle so that to combine COP image with the center of a target and to hold it in a vicinity of the last. The solution of a speed-of-response problem for change the inverted pendulum position by means of the torque in a reference point is put in compliance for this test. Speed of torque change is supposed limited. Given model allows to assume the reason of the person returnable motion at an initial stage.