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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Research on the Gearshift Control in Dual Motor Hybrid System</title>
      <link>https://trid.trb.org/View/2539457</link>
      <description><![CDATA[This paper delineates a shift control approach for a dual motor structure incorporating a drum-type shift lever in a parallel mode, which can be approximately categorized into five stages. In the first stage, the torque of the dual motor and internal combustion engine is interchanged, and the engine side torque is reverted to zero within the capacity range, with the P3 motor compensating for the torque loss on the engine side. In the second stage, the vehicle control unit transmits a request for series connection to the powertrain control module and dispatches a request for the internal combustion engine gear position to be in neutral to the powertrain control module. The powertrain control module enters the sequence for the transition from parallel to series and undertakes the action of unloading the C0 clutch torque. Once the C0 clutch torque is completely disengaged, the actual mode is fed back as parallel, and the actual engine gear position is fed back as neutral. In the third stage, upon the powertrain control module feedback of the actual series connection, the vehicle control unit internally conducts a controller area network delay judgment and subsequently requests a return to parallel, which is dispatched to the powertrain control module. Simultaneously, the new engine gear position is sent to the powertrain control module. The engine gear position at this juncture is the target gear position for parallel connection and is continuously updated. The actual engine gear position fed back by the powertrain control module is neutral, and the gear actuator commences to disengage the gear and engage the new one. In the fourth stage, the powertrain control module continues to provide feedback that the actual internal combustion engine gear position is in the N position, and the powertrain control module governs the gear actuator to engage the new gear until the engagement is accomplished. In the fifth stage, after the powertrain control module finalizes the gear engagement and the gear actuator, it increments the C0 clutch torque and aligns the C0 clutch. The outcomes of the on-vehicle verification substantiate that it assumes a vital role in enhancing driving performance.]]></description>
      <pubDate>Thu, 05 Jun 2025 11:59:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/2539457</guid>
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    <item>
      <title>Seamless shifting and suppressing clutch judder of 2-speed DCT for EV by deep reinforcement learning</title>
      <link>https://trid.trb.org/View/2448969</link>
      <description><![CDATA[One of the challenges facing widespread adoption of electric vehicles (EVs) is their short driving range. To address this challenge, the development of various EV transmissions is underway. In transmissions, clutches are used for disconnection from the drive source, and a phenomenon called judder, which is a violent vibration, may occur when the clutch slides on a frictional surface. To resolve this problem, the use of deep reinforcement learning, which is being used and advanced in areas such as machine control in simulations, was focused upon. The purpose of this study is to suppress clutch judder using deep reinforcement learning. The deep reinforcement learning model was developed for seamless gear shift control, and the gearshift results without control were compared with the gearshift results after training. As a result, a control rule that achieves seamless gear shifting while suppressing the judder is designed by applying deep reinforcement learning to gear shifting control. In addition, seamless gear shifting can be achieved for various patterns of friction coefficients, enabling the development of a robust controller for changing the friction coefficients.]]></description>
      <pubDate>Thu, 12 Dec 2024 16:58:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2448969</guid>
    </item>
    <item>
      <title>Creating of Gearshift Operation Feeling Based on a Sensitive Balance Design of Gearshift Sound, Gearshift Shock and Gearshift Operation Force</title>
      <link>https://trid.trb.org/View/2364727</link>
      <description><![CDATA[A comfortable gearshift operation feeling is created by designing suitable gearshift sound for feedback to gearshift operation by paddle shifting, etc. In addition, the acceleration feeling was improved by designing gearshift sound for each gearshift stage, taking into account changes in the sound environment during acceleration driving. In this study, a gearshift operation feeling was created by sensitive balance design of geashift sound, gearshift shock and gearshift operation force.]]></description>
      <pubDate>Wed, 17 Apr 2024 11:29:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2364727</guid>
    </item>
    <item>
      <title>Power-on downshift analysis of a seamless two-speed transmission in electric vehicles</title>
      <link>https://trid.trb.org/View/2289220</link>
      <description><![CDATA[Electric vehicles (EVs) have many advantages over internal combustion engine vehicles (ICEs) and have caught the interest of academics and industry together. The two-speed transmission of electric vehicles improves the overall power and expands the mileage of EVs. In this paper, the power-on downshifting tactics of a seamless two-speed transmission are studied. The seamless two-speed transmission is controlled by a one-way clutch and two brakes for shifting gears. Three control strategies are proposed to achieve a smooth downshifting process. Firstly, the mathematical model of the two-speed transmission for electric vehicles is constructed. Then, three downshift strategies are analysed based on a simplified mathematical model. In this study, the difference between vehicle jerk and friction work in different downshifting strategies is explored by keeping the gearshift time unchanged. After analysing the simulation results, the advantages and disadvantages of different gear downshift strategies are summarised.]]></description>
      <pubDate>Thu, 22 Feb 2024 16:14:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/2289220</guid>
    </item>
    <item>
      <title>Composite Control Law for Nonlinear Systems With Mismatched Disturbances for a Ball-Ramp Dual-Clutch Transmission</title>
      <link>https://trid.trb.org/View/2309233</link>
      <description><![CDATA[The dual-clutch transmission (DCT) was developed to increase the transmission efficiency and the shift performance. However, in a DCT, due to uncertainty related to the actuator, the tie-up phenomenon can arise, in which two clutches engage together or the clutch torque control performance deteriorates. Especially, the actuator uncertainty increased when using a special mechanism to increase controllability and efficiency. Among them, the ball-ramp DCT (BR-DCT), which uses a self-energizing mechanism, can reduce the consumption of actuator energy while also reducing the tie-up effect. However, the nonlinearity of the actuator must be considered, such as friction between parts and change in friction coefficient. Among the methods by which this type of uncertainty is estimated, the nonlinear disturbance observer is most effective when used to estimate the unmodeled nonlinearity of an actuator and time-varying uncertainty. In order to execute disturbance rejection control to improve the performance of the shift controller using the estimated uncertainty, it is necessary to configure disturbance compensation input. However, because the BR-DCT powertrain includes mismatched disturbances and nonlinearity of the actuator, it is difficult to apply the existing methods on the composite control law to shift controller. Therefore, in this study, the authors propose a composite control law to guarantee integrated stability in nonlinear systems such as a BR-DCT powertrain. The proposed method was verified through a powertrain test bench equipped with a BR-DCT. Finally, the proposed composite control law was able to converge both the tracking error and the disturbance estimation error.]]></description>
      <pubDate>Wed, 14 Feb 2024 09:15:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2309233</guid>
    </item>
    <item>
      <title>A Lyapunov based robust control of the EV gearshift process</title>
      <link>https://trid.trb.org/View/2204599</link>
      <description><![CDATA[This paper presents a novel Lyapunov based robust control algorithm for gearshift system of automated manual transmission (AMT) in electric vehicle (EV). Gearshift process is analyzed and modeled considering a two-gear powertrain. Trajectory-tracking control is designed regarding the engagement rule of the shifting fork as the desired trajectory. Model uncertainties and external disturbance are lumped into a function with the assumed upper bound. The control algorithm consists of a PD feedback component and a piecewise function component, which is error-based and model-based inheriting from conventional PID control and robust control. Furthermore, this proposed control is based on Lyapunov approach, and is theoretical proved to render uniform boundedness and uniform ultimate boundedness. The proposed control can guarantee the deterministic performance of the gearshift system, and its effectiveness is illustrated by numerical simulations and sample vehicle test.]]></description>
      <pubDate>Mon, 17 Jul 2023 15:13:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2204599</guid>
    </item>
    <item>
      <title>Gear Shifter Design – Lack of Dedicated Positions and the Contribution to Cognitive Load and Inattention</title>
      <link>https://trid.trb.org/View/1972608</link>
      <description><![CDATA[Shift-by-wire gear shifters are increasing the opportunities for individualization of functions and design. Though, greater variations can make gear shifters inefficient and error prone. Research regarding these aspects is still lacking. The aim of this study was to investigate how different gear shifter concepts were perceived in terms of Perceived Ease-of-Use and Task success, depending on their level of complexity, the shape of the shifter and stability of the shifter pattern. An experimental study was conducted with participants using six types of gear shifters on three levels of complexity. Results showed that the Monostable joystick received the lowest Perceived Ease-of-Use scores. Furthermore, the Rotary Toggle shifter with monostable function, had lowest Task success, which was supposed to be a result of e.g. unfamiliar design.]]></description>
      <pubDate>Fri, 21 Apr 2023 09:51:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/1972608</guid>
    </item>
    <item>
      <title>Fundamental Study of Jerk: Evaluation of Shift Quality and Ride Comfort</title>
      <link>https://trid.trb.org/View/1800791</link>
      <description><![CDATA[A thorough study on the physiological experience of jerk is made in this work. Referring the physiological feeling, the authors classified the jerks into two groups, which are transient jerks and durative jerks, and made a series of experiments for research. The experiment method is detailed in the literature. By reviewing the experiment results, the authors discussed the current quantifying methods of jerk and proposed a comprehensive method using magnitude of jerk and root mean square (rms) jerk for evaluating the shift quality and ride comfort. All the conclusions and proposals we made in this work are supported by experiment data.]]></description>
      <pubDate>Wed, 22 Feb 2023 09:57:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/1800791</guid>
    </item>
    <item>
      <title>Optimal control for shift mechanism of a planetary two-speed transmission for electric vehicles</title>
      <link>https://trid.trb.org/View/2026068</link>
      <description><![CDATA[For increasing mileage of electric vehicles (EVs), it is necessary to improve energy density of battery and the transmission efficiency of powertrain system. The authors designed a planetary two-speed transmission for using the high efficiency of motor effectively, which is beneficial to improve powerful and economic performances. It has an electronic mechanism replacing hydraulic system for shifting, which consists of worm gear systems driven by a brushless direct current (BLDC) motor. To improve shifting quality, the speed control of BLDC motor was developed utilising variation principle that is fitted by high order polynomials. The dynamic model of electronic actuator for shifting was built for evaluating the shifting control of the BLDC motor. The simulation results revealed that the speed of BLDC motor fitted by 5-order polynomial could make a smooth shift and low friction work of brakes compared with 3-order and 7-order polynomials.]]></description>
      <pubDate>Mon, 28 Nov 2022 10:56:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2026068</guid>
    </item>
    <item>
      <title>SHIFTER MECHANISM DESIGN for FSAE MOTOR SPORTS VEHICLE JCU</title>
      <link>https://trid.trb.org/View/1910722</link>
      <description><![CDATA[This report provides a design analysis of a replacement's shifter mechanism for the 2014 model JCU Motorsports FSAE vehicle. Common FSAE shifter mechanisms were researched and reviewed to provide a better understanding of the needs required. A design approach was constructed to ultimately design a mechanism that conformed to all existing constraints and FSAE rules. Realistic load cases were identified and employed in the FEA analysis of the design. Supporting hand calculations were developed, proving the analysis to be accurate. Results showed the shifter mechanism does not fail under infinite life, with some parts of the design having a reasonably high safety factor, ensuring stability.]]></description>
      <pubDate>Thu, 28 Apr 2022 09:40:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/1910722</guid>
    </item>
    <item>
      <title>Low Cost Robotized Gearshift System for Formula SAE Vehicles</title>
      <link>https://trid.trb.org/View/1833995</link>
      <description><![CDATA[This paper reports the studies, design and developments of an electronic electro-actuated gearshifter installed on the DP7, which is Politecnico di Milano car that took part at Formula SAE 2015 competitions in Hockenheim and Varano dè Melegari. The original idea was born to replace the hydraulic gearshift system used until 2011 because of its high weight and cost. After many evaluations about the kind of technology to use, made by previous team members in the electronic department, the final project was a fully electric shifter. This system has proven its qualities among which are lightness and low cost.]]></description>
      <pubDate>Wed, 23 Feb 2022 16:16:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/1833995</guid>
    </item>
    <item>
      <title>Optimal Gearshift Strategy in Inertia Phase of Dual-Clutch Transmissions</title>
      <link>https://trid.trb.org/View/1847595</link>
      <description><![CDATA[Shift quality is an important indicator to measure the performance of dual-clutch transmissions (DCT). To obtain optimal driving comfort and reduce the vehicle jerk as much as possible, this paper proposes an integrated gearshift controller to control the engine and the on-coming clutch in inertia phase. First of all, a dynamic model of DCT during gearshift is established. Key factors determining shift quality are analyzed. In order to reduce the vehicle jerk, a reference trajectory of the engine speed and the derivative of the desired torque transferred by the on-coming clutch in inertia phase are programmed respectively. A back-stepping sliding mode controller (BPSMC) is designed to make the actual engine speed track the reference trajectory and an incremental proportional-integrative (PI) controller is designed to make the actual clutch torque to track the desired clutch torque. At the end, simulation and experiment are carried out to validate the effectiveness of the proposed controller. Results show that the tracking error of engine speed is less than 10rad/s and the tracking error of the torque transferred by the on-coming clutch is less than 5Nm. Good tracking performance and driving comfort can be obtained using the proposed controller.]]></description>
      <pubDate>Tue, 26 Oct 2021 14:30:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/1847595</guid>
    </item>
    <item>
      <title>Electric vehicle transmission types and setups: a general review</title>
      <link>https://trid.trb.org/View/1862642</link>
      <description><![CDATA[Over the last decade, electric vehicles (EV) have changed the global automobile industry driven by the progress of electronics and powertrain systems. New controllers are manufactured and research has been made not only on motors but on transmissions as well. This paper focuses on describing the types of gearboxes available - continuous variable (CVT), automatic, manual- with their pros-cons and the experiments done with different gearsets (plan and gear numbers - single or multigear transmissions - on urban or highway cycles to maximise energy efficiency). Gearshift strategies are also a big area of interest alongside simulations testing various gear ratios handled by complex controllers and control algorithms to ensure smooth driving and performance with minimal to low jerk and torque interruption. The aim of this paper is to completely report the work done on transmission software and hardware improvements but also on the top of the shelf technology that the current EVs implement.]]></description>
      <pubDate>Fri, 27 Aug 2021 14:58:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/1862642</guid>
    </item>
    <item>
      <title>Special Crash Investigations: On-Site Vehicle Rollaway Crash Investigation; Vehicle: 2008 Pontiac G6; Location: Indiana; Crash Date: May 2018</title>
      <link>https://trid.trb.org/View/1865324</link>
      <description><![CDATA[This incident occurred in an apartment complex parking lot and involved a retention pond located approximately 15 m (50 ft) west of the parking lot. The Pontiac was a 4-door sedan with an automatic transmission and a console-mounted shift lever. A 3-year-old female occupied the vehicle at the time of the incident. Her father was outside the vehicle engaged in conversation with a witness when the Pontiac began to roll backwards across the parking lot. The vehicle traversed a grassy area and entered the retention pond. The child’s father and the witness entered the water to rescue the child. Neither the father nor the witness could swim, and the witness went back to the shore. The father retrieved the child from the vehicle and handed her to another witness who entered the pond from the far west side. The father drowned during the incident and was retrieved by police divers. He was transported by ambulance to a hospital and was pronounced dead approximately seven hours after the incident. The child occupant was transported to a hospital where she was admitted for treatment of hypothermia. The second witness was transported by ambulance to a hospital. The Pontiac was completely submerged in the pond and was recovered the following day. It was towed to police impound where it was inspected for this SCI investigation. Through the course of the investigation, it was determined that the transmission shift cable was out-of-adjustment, which gave the child the ability to shift the vehicle from the Park position to Neutral without the ignition key and without applying the brake pedal.]]></description>
      <pubDate>Tue, 27 Jul 2021 15:59:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/1865324</guid>
    </item>
    <item>
      <title>Gearshift performance improvement for an electromagnetic gearshift system based on optimized active disturbance rejection control method</title>
      <link>https://trid.trb.org/View/1712565</link>
      <description><![CDATA[Electric automated manual transmission usually adopts direct current motors and intermediate gearings to accomplish gear change. The structure can be simplified further to achieve better dynamic response and mechanical efficiency. A new type of gearshift system which adopts two electromagnetic linear actuators is presented. The intermediate gearings including motion converters are canceled, and the electromagnetic linear actuators drive the shift fork directly to move the synchronizer to engage different gears. The novel gearshift system is described in detail, including the connection, working principle, and performance. Specific working phases of the synchronization are introduced and mathematical equations of each phase are provided. After the specific feature analysis of each phase, the performance effect factors are deduced and the corresponding control requirements are proposed. Considering the stability of the performance, the robust control method, namely, active disturbance rejection control, is adopted. The time optimal method is introduced to optimize the dynamic response of the active disturbance rejection control method to achieve a shorter gearshift time. Comparative simulations among the active disturbance rejection control, time optimal–active disturbance rejection control, and proportional–integral–derivative methods show the distinct improvements of the novel gearshift system combined with the time optimal–active disturbance rejection control method. Finally, gearshift experiments are implemented. The results demonstrated the availability of the novel gearshift system and the designed control strategy.]]></description>
      <pubDate>Tue, 23 Feb 2021 10:25:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/1712565</guid>
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