55 results about "Maximum ratio transmission" patented technology

The invention discloses a design method of an automobile steering device gear sector and rack pair. The design method is characterized by comprising the following steps that initial parameters of the automobile steering device gear sector and rack pair are determined, wherein the parameters comprise the minimum transmission ratio, the maximum transmission ratio and gear sector corner values of a first adaptor point, a second adaptor point, a third adaptor point and a fourth adaptor point of a variable speed ratio curve; an integral C2-order continuous variable speed ratio curve model is established; undetermined parameters of the integral C2-order continuous variable speed ratio curve model are determined, and integral C2-order continuous variable speed ratio curves are obtained; one or more of six input parameters is/are adjusted according to the obtained integral C2-order continuous variable speed ratio curves, an integral C2-order continuous variable speed ratio curve meeting requirements is obtained, and the steering device gear sector and rack pair is designed according to the determined six input parameters. By means of the integral C2-order continuous variable speed ratio curve model and a model optimization design adjusting method, the ideal C2-order continuous variable speed ratio curve can be obtained, and design is easy and convenient.

The embodiment of the invention discloses a beam forming method of a time duplex division (TDD) multi-input multi-output (MIMO) system. The method comprises the following steps: generating the transmitted beam of a first data stream based on the maximum-ratio transmission (MRT) principle; and generating the transmitted beam of another data stream other than the first data stream, and allowing the transmitted beam of the another data stream to be restricted in the null space of the first data stream. The embodiment of the invention also discloses a base station, a receiver and a communication system. Under the condition of no feedback information, the beam forming method utilizes the reciprocity-induced imperfect channel information as much as possible, reduces the complexity, and increases the velocity of the data stream.

An apparatus and method for cooperative maximal ratio transmission in a BWA communication system are provided, in which a BS transmits a signal directed to a user terminal to an RS in a first time slot, the RS transmits the signal received from the BS to the user terminal in a second time slot, and the user terminal receives the signal from the RS.

The invention discloses a drive mechanism of a hydrodynamic transmission. The drive mechanism mainly comprises an input shaft (1), a first planet row (P1), a second planet row (P2), a third planet row (P3), a fourth planet row (P4), a first clutch (L1), a second clutch (L2), a first brake (Z1), a second brake (Z2), a third brake (Z3), a fourth brake (Z4) and an output shaft (11). The drive mechanism of the hydrodynamic transmission has the advantages that the maximum drive ratio of the drive mechanism is 7.62, gear speed ratios are even in distribution from low-speed gears to high-speed gears, and the drive mechanism is extremely suitable for working machines with large working speed variation.

A method for controlling a gear ratio rate of change in a machine having a continuously variable transmission includes moving an operator input device to a changed position, receiving electronic data indicative of the changed position, and determining a non-limited desired gear ratio based on the changed position. A maximum gear ratio rate of change corresponding to the non-limited desired gear ratio and an actual gear ratio of the continuously variable transmission is selected from an electronically stored gear ratio rate map. A current desired gear ratio is determined based on a previous desired gear ratio and the maximum gear ratio rate of change. A commanded gear ratio of the continuously variable transmission is changed to the current desired gear ratio using electronic signals.

A continuously variable transmission for a vehicle comprises a primary pulley, a secondary pulley, and a belt entrained around both pulleys in an opposite manner between the fixed and movable sheaves thereof. One pulley carries a selectively deployable stop that may be placed into position to mechanically limit the range of motion between the fixed and movable sheaves. This establishes an actual maximum transmission ratio that is larger than the nominal minimum transmission ratio but smaller than the nominal maximum transmission ratio achievable by the transmission during normal operation thereof. When such a transmission is used on a utility vehicle attached to a substance dispensing applicator operatively driven by the vehicle's engine, the application rate stays substantially constant despite changes in engine speed when the user keeps the transmission upshifted to the actual maximum transmission ratio set by the position of the deployed stop.

The invention discloses a mechanical three-shaft type high-speed-ratio automobile gearbox which comprises an input shaft, an output shaft, an intermediate shaft and transmission gears arranged on the shafts. Due to the fact that each stage of transmission gear of the gearbox is a point-line gear, running of the gearbox can be more stable, the working noise of the gearbox can be reduced, and the service life of the gearbox can be prolonged; due to the fact that the point-line gears are large short-addendum gears, the large gear ratio can be achieved, and through the design of the limit of the gear ratios of the transmission gears, the maximum transmission ratio of the first gear of the gearbox can reach above twelve, the maximization of the transmission ratio of the first gear of the gearbox is achieved, the transportation requirement for steep slope overloading of automobiles is met, an auxiliary gearbox does not need to be added in front of or in back of the gearbox, the manufacturing cost of the gearbox of a heavy-load automobile is reduced, the failure rate of the gearbox is reduced, and the reliability of the gearbox is improved; in addition, the transmission structure of the gearbox does not need to be changed, so the gear shifting operation can be more convenient and flexible.

An arrangement where a transmitter has a plurality of transmitting antennas that concurrently transmit the same symbol, and where the signal delivered to each transmitting antenna is weighted by a factor that is related to the channel transmission coefficients found between the transmitting antenna and receiving antennas. In the case of a plurality of transmit antennas and one receive antenna, where the channel coefficient between the receive antenna and a transmit antenna i is h_i, the weighting factor is h_i* divided by a normalizing factor, α, which is ${\left(\sum _{k=1}^K{h_k}^2\right)}^{1/2},$

where K is the number of transmitting antennas. When more than one receiving antenna is employed, the weighting factor is $\frac{1}{a}{\left(\mathrm{gH}\right)}^H,$

where g=[g₁ . . . g_L], H is a matrix of channel coefficients, and α is a normalizing factor ${\left(\sum _{p=1}^L\sum _{q=1}^L\sum _{k=1}^K{h}_{\mathrm{pk}}{h}_{\mathrm{qk}}^{*}\right)}^{1/2}.$

The invention relates to a massive MIMO system configuration and verification method based on multiple sub-antenna arrays. The configuration method includes the following steps: configuring a corresponding number of sub-antenna arrays according to the number of sectors uniformly divided by a service area of a massive MIMO system, wherein each sub-antenna array serves one sector correspondingly; configuring the number of antennae of each sub-antenna array according to the density of clients in each sector; obtaining an observation matrix based on mutually orthogonal pilot training sequence information that is sent by all the clients in the service area and is received by a base station end, and the total number of the antennae of the base station end, and estimating channel state information in combination with the observation matrix; and enabling the base station end to perform downlink wireless communication transmission by using the estimated channel state information and a maximum ratio transmission precoding method. According to the scheme of the invention, the energy consumption and the complexity of hardware implementation can be effectively reduced, and the spectrum efficiency of the system can also be ensured.

The invention discloses an intensive small cellular network user grouping and self-adaptive interference suppression method. The intensive small cellular network user grouping and self-adaptive interference suppression method comprises the steps that: firstly, a central processing unit groups users by utilizing large-scale fading channel information of each user, the users in the same group use the same pilot frequency, and the users of different groups use different orthogonal pilot frequencies; secondly, each small cellular base station determines adjacent intergroup interference users by utilizing the large-scale fading channel information of the users, and estimates channel vectors of the adjacent users by utilizing received uplink pilot frequency; if intergroup interference users do not exist, an uplink can adopt maximum ratio combination (MRC) reception and a downlink can adopt maximum ratio transmission (MRT) precoding; and if the intergroup interference users exist, the uplink can adopt zero-forcing reception and the downlink can adopt zero-forcing precoding transmission, so as to eliminate intergroup interference. The intensive small cellular network user grouping and self-adaptive interference suppression method can reduce pilot frequency pollution and reduce system pilot frequency overhead by adopting the simple user grouping method; moreover, the small cellular base stations eliminate the intergroup interference in a self-adaptive manner, and can effectively improve the spectral efficiency of the system.

A controller for a vehicle continuously variable transmission is disclosed. When a target gear ratio is set as the maximum gear ratio and a vehicle speed is decreased to less than a first reference vehicle speed, the controller suspends varying of the gear ratio by the transmission control and starts a gear ratio hold control that releases operational oil from a first oil pressure chamber and holds the gear ratio at the maximum gear ratio. Further, the controller ends the gear ratio hold control and delivers operational oil to the first oil pressure chamber when the vehicle speed increases to a second reference vehicle speed or greater, which is lower than the first reference vehicle speed, and restarts the varying of the gear ratio by the transmission control when the vehicle speed subsequently increases to the first reference speed or greater.

Continuously variable transmission (1) for motor vehicles, provided with a primary pulley (2) and a secondary pulley (3), around which there is arranged a drive belt (10), which is clamped between two conical pulley disks of the primary pulley (2) with a primary claming force and between two conical pulley disks of the secondary pulley (3) with a secondary clamping force, wherein, as a result of a contact angle of at least one of the pulley disks of the respective pulleys (2; 3) with the drive belt (10) being adapted, and at least in the largest transmission ratio of the transmission (1), i.e. Low, a clamping force ratio between the primary clamping force and the secondary clamping force has a value in the range between 1 and the clamping force ratio in the smallest transmission ratio, i.e. Overdrive.

A system includes a continuously variable transmission having a primary pulley assembly configured to receive power and a primary oil chamber coupled to the primary pulley assembly such that a pressure of oil within the primary oil chamber is applied to the primary pulley assembly. The continuously variable transmission also includes a secondary pulley assembly and a drive belt configured to transfer power from the primary pulley assembly to the secondary pulley assembly. The system also includes a pressure sensor coupled to the primary oil chamber and configured to detect a pressure of the oil within the primary oil chamber. The system also includes an electronic control unit coupled to the pressure sensor and configured to determine whether the continuously variable transmission is set to the maximum gear ratio based on the detected pressure of the oil within the primary oil chamber.

A gearbox for vehicles that include a split gearbox, a main gearbox and a range gearbox. The range gearbox is shiftable into a low range gear, a high range gear and a reverse gear. The range gearbox includes a planetary gear, which may be shifted into a reverse gear. The split gearbox and the main gearbox are together arranged to have a combined ratio spread larger than 5, in that the split gearbox and the main gearbox are together arranged to have a combined largest gear ratio over 4:1, and in that the planetary gear in the range gearbox has a gear ratio less than 4:1 when shifted into the reverse gear.

A propulsion system, control system, and method use model predictive control systems to generate a plurality of sets of possible command values and determine a cost for each set of possible command values. The set of possible command values that has the lowest cost is determined and defined as a selected set of command values. In some circumstances, the MPC-determined command value may be replacedby another transmission ratio command based on override inputs. Minimum and maximum transmission ratios are determined based on the override inputs, and a constrained (or arbitrated) transmission ratio is determined therefrom. The constrained or arbitrated transmission ratio is used to determine whether to apply an MPC-determined transmission ratio or a transmission ratio based on the arbitratedtransmission ratio to determine an ultimate commanded transmission ratio. Pressure(s) are commanded to a transmission pulley assembly, which is configured to implement the ultimate commanded transmission ratio.

The invention discloses an adaptive power allocation method for a wireless powered communication system. The method comprises the steps that channel state information and time slot allocation taut areinitialized; an energy access point carries out beam forming through utilization of the maximum ratio transmission technology and transmits energy beam to a data access point; and the data access point receives the energy beam of the energy access point, converts the energy beam into total transmission power, determines the number l of antennas in a transmission antenna subset according to powercontrol of antennas and the total transmission power, selects l transmission antennas with good data channel states as the transmission antenna subset, carries out equal power allocation on the transmission antenna subset and transmits required data to a wireless device through utilization of the maximum ratio transmission technology. According to the method, under the condition that power limitation exists in the antennas, adaptive allocation of the collected energy with randomness is realized, and utilization efficiency of the collected energy and reliability of the communication system areimproved.

The invention discloses a transmission ratio obtaining method for improving vehicle power performance, and belongs to the technical field of vehicle transmission. The implementation method comprises the steps of determining the upper boundary of the transmission ratio according to vehicle parameters, design indexes and road adhesion; determining a transmission ratio lower boundary according to thehighest vehicle speed, the wheel radius, main transmission and the maximum rotating speed of a power system; on the basis of a gradient speed ratio differential acquisition formula, acquiring an improved dynamic transmission ratio formula by increasing an adjustment coefficient; according to different power performance requirements, selecting corresponding adjustment coefficients and substitutingthe maximum transmission ratio, the minimum transmission ratio and the gear number into an improved power transmission ratio acquisition formula to obtain a transmission ratio meeting the corresponding performance requirements, so that the power performance of the vehicle under different performance requirements is improved, and the performance of a vehicle power device is brought into full play.According to the method, the high vehicle power performance transmission ratio is obtained through a formula analysis method, dependence on an accurate model is not needed, and the method has the advantages of being good in universality and high in transmission ratio obtaining efficiency.

The invention discloses a double-limit zero-return device for a servo shaft of a numerically controlled machine tool, which comprises a first machine tool collision block, a first non-contact point proximity switch, a second machine tool collision block, a second non-contact point proximity switch, a servo motor and a programmable controller, wherein the first machine tool collision block and the first non-contact point proximity switch are mounted on the last transmission wheel of the servo shaft; the second machine tool collision block and the second non-contact point proximity switch are mounted on a low-gear-ratio gear; the ratio of the low-gear-ratio gear is higher than that of a gear of which the gear ratio is the lowest, and smaller than a gear of which the gear ratio is the highest; the servo motor is used for controlling the operation of the numerically controlled machine tool; and the I/O terminal of the programmable controller is electrically connected with the first non-contact point proximity switch, the second non-contact point proximity switch and the control terminal of the servo motor. The double-limit zero-return device has the advantage that when a monitoring result shows that the first non-contact point proximity switch mounted on a large gear generates a positive pulse signal, and another positive pulse signal generated by the second non-contact point proximity switch mounted on a gear of which the gear ratio is relatively low can play the role of searching zero pulses of a reference point. Therefore, each zero-return position of the servo shaft of the numerically controlled machine tool can be more accurate and stabler.